Fix a crash when threading a block that includes a MRV call result.

DemoteRegToStack doesn't work with MRVs yet, because it relies on the
ability to load/store things.

This fixes PR2285.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50667 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 44 insertions, 4 deletions

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index be94025..1a2ec99 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -433,12 +433,27 @@ void JumpThreading::ThreadEdge(BasicBlock *BB, BasicBlock *PredBB,
   // Jump Threading can not update SSA properties correctly if the values
   // defined in the duplicated block are used outside of the block itself.  For
   // this reason, we spill all values that are used outside of BB to the stack.
-  for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I)
-    if (I->isUsedOutsideOfBlock(BB)) {
-      // We found a use of I outside of BB.  Create a new stack slot to
-      // break this inter-block usage pattern.
+  for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
+    if (!I->isUsedOutsideOfBlock(BB))
+      continue;
+    
+    // We found a use of I outside of BB.  Create a new stack slot to
+    // break this inter-block usage pattern.
+    if (!isa<StructType>(I->getType())) {
       DemoteRegToStack(*I);
+      continue;
     }
+    
+    // Alternatively, I must be a call or invoke that returns multiple retvals.
+    // We can't use 'DemoteRegToStack' because the at will create loads and
+    // stores of aggregates which is not valid yet.  If I is a call, we can just
+    // pull all the getresult instructions up to this block.  If I is an invoke,
+    // we are out of luck.
+    BasicBlock::iterator IP = I; ++IP;
+    for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+         UI != E; ++UI)
+      cast<GetResultInst>(UI)->moveBefore(IP);
+  }
  
   // We are going to have to map operands from the original BB block to the new
   // copy of the block 'NewBB'.  If there are PHI nodes in BB, evaluate them to
diff --git a/test/Transforms/JumpThreading/2008-05-05-MRV-Crash.ll b/test/Transforms/JumpThreading/2008-05-05-MRV-Crash.ll
new file mode 100644
index 0000000..f109109
--- /dev/null
+++ b/test/Transforms/JumpThreading/2008-05-05-MRV-Crash.ll
@@ -0,0 +1,25 @@
+; RUN: llvm-as < %s | opt -jump-threading -disable-output
+; PR2285
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+	%struct.system__secondary_stack__mark_id = type { i64, i64 }
+
+define void @_ada_c35507b() {
+entry:
+	br label %bb
+
+bb:		; preds = %bb13, %entry
+	%ch.0 = phi i8 [ 0, %entry ], [ 0, %bb13 ]		; <i8> [#uses=1]
+	%tmp11 = icmp ugt i8 %ch.0, 31		; <i1> [#uses=1]
+	%tmp120 = call %struct.system__secondary_stack__mark_id @system__secondary_stack__ss_mark( )		; <%struct.system__secondary_stack__mark_id> [#uses=1]
+	br i1 %tmp11, label %bb110, label %bb13
+
+bb13:		; preds = %bb
+	br label %bb
+
+bb110:		; preds = %bb
+	%mrv_gr124 = getresult %struct.system__secondary_stack__mark_id %tmp120, 1		; <i64> [#uses=0]
+	unreachable
+}
+
+declare %struct.system__secondary_stack__mark_id @system__secondary_stack__ss_mark()