llvmpipe: export the tgsi translation code to a common layer

the llvmpipe tgsi translation is a lot more complete than what was in
gallivm so replacing the latter with the former. this is needed since
the draw llvm paths will use the same code. effectively the proven
llvmpipe code becomes gallivm.

1 files changed, 757 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_flow.c b/src/gallium/auxiliary/gallivm/lp_bld_flow.c
new file mode 100644
index 0000000..bc83138
--- /dev/null
+++ b/src/gallium/auxiliary/gallivm/lp_bld_flow.c
@@ -0,0 +1,757 @@
+/**************************************************************************
+ *
+ * Copyright 2009 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+/**
+ * LLVM control flow build helpers.
+ *
+ * @author Jose Fonseca <jfonseca@vmware.com>
+ */
+
+#include "util/u_debug.h"
+#include "util/u_memory.h"
+
+#include "lp_bld_type.h"
+#include "lp_bld_flow.h"
+
+
+#define LP_BUILD_FLOW_MAX_VARIABLES 32
+#define LP_BUILD_FLOW_MAX_DEPTH 32
+
+/**
+ * Enumeration of all possible flow constructs.
+ */
+enum lp_build_flow_construct_kind {
+   LP_BUILD_FLOW_SCOPE,
+   LP_BUILD_FLOW_SKIP,
+   LP_BUILD_FLOW_IF
+};
+
+
+/**
+ * Variable declaration scope.
+ */
+struct lp_build_flow_scope
+{
+   /** Number of variables declared in this scope */
+   unsigned num_variables;
+};
+
+
+/**
+ * Early exit. Useful to skip to the end of a function or block when
+ * the execution mask becomes zero or when there is an error condition.
+ */
+struct lp_build_flow_skip
+{
+   /** Block to skip to */
+   LLVMBasicBlockRef block;
+
+   /** Number of variables declared at the beginning */
+   unsigned num_variables;
+
+   LLVMValueRef *phi;  /**< array [num_variables] */
+};
+
+
+/**
+ * if/else/endif.
+ */
+struct lp_build_flow_if
+{
+   unsigned num_variables;
+
+   LLVMValueRef *phi;  /**< array [num_variables] */
+
+   LLVMValueRef condition;
+   LLVMBasicBlockRef entry_block, true_block, false_block, merge_block;
+};
+
+
+/**
+ * Union of all possible flow constructs' data
+ */
+union lp_build_flow_construct_data
+{
+   struct lp_build_flow_scope scope;
+   struct lp_build_flow_skip skip;
+   struct lp_build_flow_if ifthen;
+};
+
+
+/**
+ * Element of the flow construct stack.
+ */
+struct lp_build_flow_construct
+{
+   enum lp_build_flow_construct_kind kind;
+   union lp_build_flow_construct_data data;
+};
+
+
+/**
+ * All necessary data to generate LLVM control flow constructs.
+ *
+ * Besides keeping track of the control flow construct themselves we also
+ * need to keep track of variables in order to generate SSA Phi values.
+ */
+struct lp_build_flow_context
+{
+   LLVMBuilderRef builder;
+
+   /**
+    * Control flow stack.
+    */
+   struct lp_build_flow_construct constructs[LP_BUILD_FLOW_MAX_DEPTH];
+   unsigned num_constructs;
+
+   /**
+    * Variable stack
+    */
+   LLVMValueRef *variables[LP_BUILD_FLOW_MAX_VARIABLES];
+   unsigned num_variables;
+};
+
+
+struct lp_build_flow_context *
+lp_build_flow_create(LLVMBuilderRef builder)
+{
+   struct lp_build_flow_context *flow;
+
+   flow = CALLOC_STRUCT(lp_build_flow_context);
+   if(!flow)
+      return NULL;
+
+   flow->builder = builder;
+
+   return flow;
+}
+
+
+void
+lp_build_flow_destroy(struct lp_build_flow_context *flow)
+{
+   assert(flow->num_constructs == 0);
+   assert(flow->num_variables == 0);
+   FREE(flow);
+}
+
+
+/**
+ * Begin/push a new flow control construct, such as a loop, skip block
+ * or variable scope.
+ */
+static union lp_build_flow_construct_data *
+lp_build_flow_push(struct lp_build_flow_context *flow,
+                   enum lp_build_flow_construct_kind kind)
+{
+   assert(flow->num_constructs < LP_BUILD_FLOW_MAX_DEPTH);
+   if(flow->num_constructs >= LP_BUILD_FLOW_MAX_DEPTH)
+      return NULL;
+
+   flow->constructs[flow->num_constructs].kind = kind;
+   return &flow->constructs[flow->num_constructs++].data;
+}
+
+
+/**
+ * Return the current/top flow control construct on the stack.
+ * \param kind  the expected type of the top-most construct
+ */
+static union lp_build_flow_construct_data *
+lp_build_flow_peek(struct lp_build_flow_context *flow,
+                   enum lp_build_flow_construct_kind kind)
+{
+   assert(flow->num_constructs);
+   if(!flow->num_constructs)
+      return NULL;
+
+   assert(flow->constructs[flow->num_constructs - 1].kind == kind);
+   if(flow->constructs[flow->num_constructs - 1].kind != kind)
+      return NULL;
+
+   return &flow->constructs[flow->num_constructs - 1].data;
+}
+
+
+/**
+ * End/pop the current/top flow control construct on the stack.
+ * \param kind  the expected type of the top-most construct
+ */
+static union lp_build_flow_construct_data *
+lp_build_flow_pop(struct lp_build_flow_context *flow,
+                  enum lp_build_flow_construct_kind kind)
+{
+   assert(flow->num_constructs);
+   if(!flow->num_constructs)
+      return NULL;
+
+   assert(flow->constructs[flow->num_constructs - 1].kind == kind);
+   if(flow->constructs[flow->num_constructs - 1].kind != kind)
+      return NULL;
+
+   return &flow->constructs[--flow->num_constructs].data;
+}
+
+
+/**
+ * Begin a variable scope.
+ *
+ *
+ */
+void
+lp_build_flow_scope_begin(struct lp_build_flow_context *flow)
+{
+   struct lp_build_flow_scope *scope;
+
+   scope = &lp_build_flow_push(flow, LP_BUILD_FLOW_SCOPE)->scope;
+   if(!scope)
+      return;
+
+   scope->num_variables = 0;
+}
+
+
+/**
+ * Declare a variable.
+ *
+ * A variable is a named entity which can have different LLVMValueRef's at
+ * different points of the program. This is relevant for control flow because
+ * when there are multiple branches to a same location we need to replace
+ * the variable's value with a Phi function as explained in
+ * http://en.wikipedia.org/wiki/Static_single_assignment_form .
+ *
+ * We keep track of variables by keeping around a pointer to where they're
+ * current.
+ *
+ * There are a few cautions to observe:
+ *
+ * - Variable's value must not be NULL. If there is no initial value then
+ *   LLVMGetUndef() should be used.
+ *
+ * - Variable's value must be kept up-to-date. If the variable is going to be
+ *   modified by a function then a pointer should be passed so that its value
+ *   is accurate. Failure to do this will cause some of the variables'
+ *   transient values to be lost, leading to wrong results.
+ *
+ * - A program should be written from top to bottom, by always appending
+ *   instructions to the bottom with a single LLVMBuilderRef. Inserting and/or
+ *   modifying existing statements will most likely lead to wrong results.
+ *
+ */
+void
+lp_build_flow_scope_declare(struct lp_build_flow_context *flow,
+                            LLVMValueRef *variable)
+{
+   struct lp_build_flow_scope *scope;
+
+   scope = &lp_build_flow_peek(flow, LP_BUILD_FLOW_SCOPE)->scope;
+   if(!scope)
+      return;
+
+   assert(*variable);
+   if(!*variable)
+      return;
+
+   assert(flow->num_variables < LP_BUILD_FLOW_MAX_VARIABLES);
+   if(flow->num_variables >= LP_BUILD_FLOW_MAX_VARIABLES)
+      return;
+
+   flow->variables[flow->num_variables++] = variable;
+   ++scope->num_variables;
+}
+
+
+void
+lp_build_flow_scope_end(struct lp_build_flow_context *flow)
+{
+   struct lp_build_flow_scope *scope;
+
+   scope = &lp_build_flow_pop(flow, LP_BUILD_FLOW_SCOPE)->scope;
+   if(!scope)
+      return;
+
+   assert(flow->num_variables >= scope->num_variables);
+   if(flow->num_variables < scope->num_variables) {
+      flow->num_variables = 0;
+      return;
+   }
+
+   flow->num_variables -= scope->num_variables;
+}
+
+
+/**
+ * Note: this function has no dependencies on the flow code and could
+ * be used elsewhere.
+ */
+static LLVMBasicBlockRef
+lp_build_insert_new_block(LLVMBuilderRef builder, const char *name)
+{
+   LLVMBasicBlockRef current_block;
+   LLVMBasicBlockRef next_block;
+   LLVMBasicBlockRef new_block;
+
+   /* get current basic block */
+   current_block = LLVMGetInsertBlock(builder);
+
+   /* check if there's another block after this one */
+   next_block = LLVMGetNextBasicBlock(current_block);
+   if (next_block) {
+      /* insert the new block before the next block */
+      new_block = LLVMInsertBasicBlock(next_block, name);
+   }
+   else {
+      /* append new block after current block */
+      LLVMValueRef function = LLVMGetBasicBlockParent(current_block);
+      new_block = LLVMAppendBasicBlock(function, name);
+   }
+
+   return new_block;
+}
+
+
+static LLVMBasicBlockRef
+lp_build_flow_insert_block(struct lp_build_flow_context *flow)
+{
+   return lp_build_insert_new_block(flow->builder, "");
+}
+
+
+/**
+ * Begin a "skip" block.  Inside this block we can test a condition and
+ * skip to the end of the block if the condition is false.
+ */
+void
+lp_build_flow_skip_begin(struct lp_build_flow_context *flow)
+{
+   struct lp_build_flow_skip *skip;
+   LLVMBuilderRef builder;
+   unsigned i;
+
+   skip = &lp_build_flow_push(flow, LP_BUILD_FLOW_SKIP)->skip;
+   if(!skip)
+      return;
+
+   /* create new basic block */
+   skip->block = lp_build_flow_insert_block(flow);
+
+   skip->num_variables = flow->num_variables;
+   if(!skip->num_variables) {
+      skip->phi = NULL;
+      return;
+   }
+
+   /* Allocate a Phi node for each variable in this skip scope */
+   skip->phi = MALLOC(skip->num_variables * sizeof *skip->phi);
+   if(!skip->phi) {
+      skip->num_variables = 0;
+      return;
+   }
+
+   builder = LLVMCreateBuilder();
+   LLVMPositionBuilderAtEnd(builder, skip->block);
+
+   /* create a Phi node for each variable */
+   for(i = 0; i < skip->num_variables; ++i)
+      skip->phi[i] = LLVMBuildPhi(builder, LLVMTypeOf(*flow->variables[i]), "");
+
+   LLVMDisposeBuilder(builder);
+}
+
+
+/**
+ * Insert code to test a condition and branch to the end of the current
+ * skip block if the condition is true.
+ */
+void
+lp_build_flow_skip_cond_break(struct lp_build_flow_context *flow,
+                              LLVMValueRef cond)
+{
+   struct lp_build_flow_skip *skip;
+   LLVMBasicBlockRef current_block;
+   LLVMBasicBlockRef new_block;
+   unsigned i;
+
+   skip = &lp_build_flow_peek(flow, LP_BUILD_FLOW_SKIP)->skip;
+   if(!skip)
+      return;
+
+   current_block = LLVMGetInsertBlock(flow->builder);
+
+   new_block = lp_build_flow_insert_block(flow);
+
+   /* for each variable, update the Phi node with a (variable, block) pair */
+   for(i = 0; i < skip->num_variables; ++i) {
+      assert(*flow->variables[i]);
+      LLVMAddIncoming(skip->phi[i], flow->variables[i], &current_block, 1);
+   }
+
+   /* if cond is true, goto skip->block, else goto new_block */
+   LLVMBuildCondBr(flow->builder, cond, skip->block, new_block);
+
+   LLVMPositionBuilderAtEnd(flow->builder, new_block);
+}
+
+
+void
+lp_build_flow_skip_end(struct lp_build_flow_context *flow)
+{
+   struct lp_build_flow_skip *skip;
+   LLVMBasicBlockRef current_block;
+   unsigned i;
+
+   skip = &lp_build_flow_pop(flow, LP_BUILD_FLOW_SKIP)->skip;
+   if(!skip)
+      return;
+
+   current_block = LLVMGetInsertBlock(flow->builder);
+
+   /* add (variable, block) tuples to the phi nodes */
+   for(i = 0; i < skip->num_variables; ++i) {
+      assert(*flow->variables[i]);
+      LLVMAddIncoming(skip->phi[i], flow->variables[i], &current_block, 1);
+      *flow->variables[i] = skip->phi[i];
+   }
+
+   /* goto block */
+   LLVMBuildBr(flow->builder, skip->block);
+   LLVMPositionBuilderAtEnd(flow->builder, skip->block);
+
+   FREE(skip->phi);
+}
+
+
+/**
+ * Check if the mask predicate is zero.  If so, jump to the end of the block.
+ */
+static void
+lp_build_mask_check(struct lp_build_mask_context *mask)
+{
+   LLVMBuilderRef builder = mask->flow->builder;
+   LLVMValueRef cond;
+
+   /* cond = (mask == 0) */
+   cond = LLVMBuildICmp(builder,
+                        LLVMIntEQ,
+                        LLVMBuildBitCast(builder, mask->value, mask->reg_type, ""),
+                        LLVMConstNull(mask->reg_type),
+                        "");
+
+   /* if cond, goto end of block */
+   lp_build_flow_skip_cond_break(mask->flow, cond);
+}
+
+
+/**
+ * Begin a section of code which is predicated on a mask.
+ * \param mask  the mask context, initialized here
+ * \param flow  the flow context
+ * \param type  the type of the mask
+ * \param value  storage for the mask
+ */
+void
+lp_build_mask_begin(struct lp_build_mask_context *mask,
+                    struct lp_build_flow_context *flow,
+                    struct lp_type type,
+                    LLVMValueRef value)
+{
+   memset(mask, 0, sizeof *mask);
+
+   mask->flow = flow;
+   mask->reg_type = LLVMIntType(type.width * type.length);
+   mask->value = value;
+
+   lp_build_flow_scope_begin(flow);
+   lp_build_flow_scope_declare(flow, &mask->value);
+   lp_build_flow_skip_begin(flow);
+
+   lp_build_mask_check(mask);
+}
+
+
+/**
+ * Update boolean mask with given value (bitwise AND).
+ * Typically used to update the quad's pixel alive/killed mask
+ * after depth testing, alpha testing, TGSI_OPCODE_KIL, etc.
+ */
+void
+lp_build_mask_update(struct lp_build_mask_context *mask,
+                     LLVMValueRef value)
+{
+   mask->value = LLVMBuildAnd( mask->flow->builder, mask->value, value, "");
+
+   lp_build_mask_check(mask);
+}
+
+
+/**
+ * End section of code which is predicated on a mask.
+ */
+LLVMValueRef
+lp_build_mask_end(struct lp_build_mask_context *mask)
+{
+   lp_build_flow_skip_end(mask->flow);
+   lp_build_flow_scope_end(mask->flow);
+   return mask->value;
+}
+
+
+
+void
+lp_build_loop_begin(LLVMBuilderRef builder,
+                    LLVMValueRef start,
+                    struct lp_build_loop_state *state)
+{
+   LLVMBasicBlockRef block = LLVMGetInsertBlock(builder);
+   LLVMValueRef function = LLVMGetBasicBlockParent(block);
+
+   state->block = LLVMAppendBasicBlock(function, "loop");
+
+   LLVMBuildBr(builder, state->block);
+
+   LLVMPositionBuilderAtEnd(builder, state->block);
+
+   state->counter = LLVMBuildPhi(builder, LLVMTypeOf(start), "");
+
+   LLVMAddIncoming(state->counter, &start, &block, 1);
+
+}
+
+
+void
+lp_build_loop_end(LLVMBuilderRef builder,
+                  LLVMValueRef end,
+                  LLVMValueRef step,
+                  struct lp_build_loop_state *state)
+{
+   LLVMBasicBlockRef block = LLVMGetInsertBlock(builder);
+   LLVMValueRef function = LLVMGetBasicBlockParent(block);
+   LLVMValueRef next;
+   LLVMValueRef cond;
+   LLVMBasicBlockRef after_block;
+
+   if (!step)
+      step = LLVMConstInt(LLVMTypeOf(end), 1, 0);
+
+   next = LLVMBuildAdd(builder, state->counter, step, "");
+
+   cond = LLVMBuildICmp(builder, LLVMIntNE, next, end, "");
+
+   after_block = LLVMAppendBasicBlock(function, "");
+
+   LLVMBuildCondBr(builder, cond, after_block, state->block);
+
+   LLVMAddIncoming(state->counter, &next, &block, 1);
+
+   LLVMPositionBuilderAtEnd(builder, after_block);
+}
+
+
+
+/*
+  Example of if/then/else building:
+
+     int x;
+     if (cond) {
+        x = 1 + 2;
+     }
+     else {
+        x = 2 + 3;
+     }
+
+  Is built with:
+
+     LLVMValueRef x = LLVMGetUndef();  // or something else
+
+     flow = lp_build_flow_create(builder);
+
+        lp_build_flow_scope_begin(flow);
+
+           // x needs a phi node
+           lp_build_flow_scope_declare(flow, &x);
+
+           lp_build_if(ctx, flow, builder, cond);
+              x = LLVMAdd(1, 2);
+           lp_build_else(ctx);
+              x = LLVMAdd(2, 3);
+           lp_build_endif(ctx);
+
+        lp_build_flow_scope_end(flow);
+
+     lp_build_flow_destroy(flow);
+ */
+
+
+
+/**
+ * Begin an if/else/endif construct.
+ */
+void
+lp_build_if(struct lp_build_if_state *ctx,
+            struct lp_build_flow_context *flow,
+            LLVMBuilderRef builder,
+            LLVMValueRef condition)
+{
+   LLVMBasicBlockRef block = LLVMGetInsertBlock(builder);
+   struct lp_build_flow_if *ifthen;
+   unsigned i;
+
+   memset(ctx, 0, sizeof(*ctx));
+   ctx->builder = builder;
+   ctx->flow = flow;
+
+   /* push/create new scope */
+   ifthen = &lp_build_flow_push(flow, LP_BUILD_FLOW_IF)->ifthen;
+   assert(ifthen);
+
+   ifthen->num_variables = flow->num_variables;
+   ifthen->condition = condition;
+   ifthen->entry_block = block;
+
+   /* create a Phi node for each variable in this flow scope */
+   ifthen->phi = MALLOC(ifthen->num_variables * sizeof(*ifthen->phi));
+   if (!ifthen->phi) {
+      ifthen->num_variables = 0;
+      return;
+   }
+
+   /* create endif/merge basic block for the phi functions */
+   ifthen->merge_block = lp_build_insert_new_block(builder, "endif-block");
+   LLVMPositionBuilderAtEnd(builder, ifthen->merge_block);
+
+   /* create a phi node for each variable */
+   for (i = 0; i < flow->num_variables; i++) {
+      ifthen->phi[i] = LLVMBuildPhi(builder, LLVMTypeOf(*flow->variables[i]), "");
+
+      /* add add the initial value of the var from the entry block */
+      LLVMAddIncoming(ifthen->phi[i], flow->variables[i], &ifthen->entry_block, 1);
+   }
+
+   /* create/insert true_block before merge_block */
+   ifthen->true_block = LLVMInsertBasicBlock(ifthen->merge_block, "if-true-block");
+
+   /* successive code goes into the true block */
+   LLVMPositionBuilderAtEnd(builder, ifthen->true_block);
+}
+
+
+/**
+ * Begin else-part of a conditional
+ */
+void
+lp_build_else(struct lp_build_if_state *ctx)
+{
+   struct lp_build_flow_context *flow = ctx->flow;
+   struct lp_build_flow_if *ifthen;
+   unsigned i;
+
+   ifthen = &lp_build_flow_peek(flow, LP_BUILD_FLOW_IF)->ifthen;
+   assert(ifthen);
+
+   /* for each variable, update the Phi node with a (variable, block) pair */
+   LLVMPositionBuilderAtEnd(ctx->builder, ifthen->merge_block);
+   for (i = 0; i < flow->num_variables; i++) {
+      assert(*flow->variables[i]);
+      LLVMAddIncoming(ifthen->phi[i], flow->variables[i], &ifthen->true_block, 1);
+   }
+
+   /* create/insert false_block before the merge block */
+   ifthen->false_block = LLVMInsertBasicBlock(ifthen->merge_block, "if-false-block");
+
+   /* successive code goes into the else block */
+   LLVMPositionBuilderAtEnd(ctx->builder, ifthen->false_block);
+}
+
+
+/**
+ * End a conditional.
+ */
+void
+lp_build_endif(struct lp_build_if_state *ctx)
+{
+   struct lp_build_flow_context *flow = ctx->flow;
+   struct lp_build_flow_if *ifthen;
+   unsigned i;
+
+   ifthen = &lp_build_flow_pop(flow, LP_BUILD_FLOW_IF)->ifthen;
+   assert(ifthen);
+
+   if (ifthen->false_block) {
+      LLVMPositionBuilderAtEnd(ctx->builder, ifthen->merge_block);
+      /* for each variable, update the Phi node with a (variable, block) pair */
+      for (i = 0; i < flow->num_variables; i++) {
+         assert(*flow->variables[i]);
+         LLVMAddIncoming(ifthen->phi[i], flow->variables[i], &ifthen->false_block, 1);
+
+         /* replace the variable ref with the phi function */
+         *flow->variables[i] = ifthen->phi[i];
+      }
+   }
+   else {
+      /* no else clause */
+      LLVMPositionBuilderAtEnd(ctx->builder, ifthen->merge_block);
+      for (i = 0; i < flow->num_variables; i++) {
+         assert(*flow->variables[i]);
+         LLVMAddIncoming(ifthen->phi[i], flow->variables[i], &ifthen->true_block, 1);
+
+         /* replace the variable ref with the phi function */
+         *flow->variables[i] = ifthen->phi[i];
+      }
+   }
+
+   FREE(ifthen->phi);
+
+   /***
+    *** Now patch in the various branch instructions.
+    ***/
+
+   /* Insert the conditional branch instruction at the end of entry_block */
+   LLVMPositionBuilderAtEnd(ctx->builder, ifthen->entry_block);
+   if (ifthen->false_block) {
+      /* we have an else clause */
+      LLVMBuildCondBr(ctx->builder, ifthen->condition,
+                      ifthen->true_block, ifthen->false_block);
+   }
+   else {
+      /* no else clause */
+      LLVMBuildCondBr(ctx->builder, ifthen->condition,
+                      ifthen->true_block, ifthen->merge_block);
+   }
+
+   /* Append an unconditional Br(anch) instruction on the true_block */
+   LLVMPositionBuilderAtEnd(ctx->builder, ifthen->true_block);
+   LLVMBuildBr(ctx->builder, ifthen->merge_block);
+   if (ifthen->false_block) {
+      /* Append an unconditional Br(anch) instruction on the false_block */
+      LLVMPositionBuilderAtEnd(ctx->builder, ifthen->false_block);
+      LLVMBuildBr(ctx->builder, ifthen->merge_block);
+   }
+
+
+   /* Resume building code at end of the ifthen->merge_block */
+   LLVMPositionBuilderAtEnd(ctx->builder, ifthen->merge_block);
+}