diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 19 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll | 30 |
2 files changed, 42 insertions, 7 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index c707e6e..86aca07 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -9432,16 +9432,21 @@ Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { // Insert and return the new operation. if (CastInst* FirstCI = dyn_cast<CastInst>(FirstInst)) return CastInst::create(FirstCI->getOpcode(), PhiVal, PN.getType()); - else if (isa<LoadInst>(FirstInst)) - return new LoadInst(PhiVal, "", isVolatile); - else if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst)) + if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst)) return BinaryOperator::create(BinOp->getOpcode(), PhiVal, ConstantOp); - else if (CmpInst *CIOp = dyn_cast<CmpInst>(FirstInst)) + if (CmpInst *CIOp = dyn_cast<CmpInst>(FirstInst)) return CmpInst::create(CIOp->getOpcode(), CIOp->getPredicate(), PhiVal, ConstantOp); - else - assert(0 && "Unknown operation"); - return 0; + assert(isa<LoadInst>(FirstInst) && "Unknown operation"); + + // If this was a volatile load that we are merging, make sure to loop through + // and mark all the input loads as non-volatile. If we don't do this, we will + // insert a new volatile load and the old ones will not be deletable. + if (isVolatile) + for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) + cast<LoadInst>(PN.getIncomingValue(i))->setVolatile(false); + + return new LoadInst(PhiVal, "", isVolatile); } /// DeadPHICycle - Return true if this PHI node is only used by a PHI node cycle diff --git a/test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll b/test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll new file mode 100644 index 0000000..9f378cc --- /dev/null +++ b/test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll @@ -0,0 +1,30 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {volatile load} | count 1 +; PR2262 +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" +target triple = "i386-apple-darwin8" +@g_1 = internal global i32 0 ; <i32*> [#uses=3] +@.str = internal constant [13 x i8] c"checksum = 0\00" ; <[13 x i8]*> [#uses=1] +@llvm.used = appending global [1 x i8*] [ i8* bitcast (i32 ()* @main to i8*) ], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0] + +define i32 @main() nounwind { +entry: + %tmp93 = icmp slt i32 0, 10 ; <i1> [#uses=0] + %tmp34 = volatile load i32* @g_1, align 4 ; <i32> [#uses=1] + br label %bb + +bb: ; preds = %bb, %entry + %b.0.reg2mem.0 = phi i32 [ 0, %entry ], [ %tmp6, %bb ] ; <i32> [#uses=1] + %tmp3.reg2mem.0 = phi i32 [ %tmp34, %entry ], [ %tmp3, %bb ] ; <i32> [#uses=1] + %tmp4 = add i32 %tmp3.reg2mem.0, 5 ; <i32> [#uses=1] + volatile store i32 %tmp4, i32* @g_1, align 4 + %tmp6 = add i32 %b.0.reg2mem.0, 1 ; <i32> [#uses=2] + %tmp9 = icmp slt i32 %tmp6, 10 ; <i1> [#uses=1] + %tmp3 = volatile load i32* @g_1, align 4 ; <i32> [#uses=1] + br i1 %tmp9, label %bb, label %bb11 + +bb11: ; preds = %bb + %tmp14 = call i32 @puts( i8* getelementptr ([13 x i8]* @.str, i32 0, i32 0) ) nounwind ; <i32> [#uses=0] + ret i32 0 +} + +declare i32 @puts(i8*) |