diff options
| -rw-r--r-- | lib/Transforms/Scalar/LoopInstSimplify.cpp | 10 | ||||
| -rw-r--r-- | lib/Transforms/Utils/SimplifyInstructions.cpp | 10 | ||||
| -rw-r--r-- | test/Transforms/InstSimplify/dead-code-removal.ll | 15 |
3 files changed, 33 insertions, 2 deletions
diff --git a/lib/Transforms/Scalar/LoopInstSimplify.cpp b/lib/Transforms/Scalar/LoopInstSimplify.cpp index a61923cabf..ab1a9393c5 100644 --- a/lib/Transforms/Scalar/LoopInstSimplify.cpp +++ b/lib/Transforms/Scalar/LoopInstSimplify.cpp @@ -127,7 +127,15 @@ bool LoopInstSimplify::runOnLoop(Loop *L, LPPassManager &LPM) { ++NumSimplified; } } - LocalChanged |= RecursivelyDeleteTriviallyDeadInstructions(I, TLI); + bool res = RecursivelyDeleteTriviallyDeadInstructions(I, TLI); + if (res) { + // RecursivelyDeleteTriviallyDeadInstruction can remove + // more than one instruction, so simply incrementing the + // iterator does not work. When instructions get deleted + // re-iterate instead. + BI = BB->begin(); BE = BB->end(); + LocalChanged |= res; + } if (IsSubloopHeader && !isa<PHINode>(I)) break; diff --git a/lib/Transforms/Utils/SimplifyInstructions.cpp b/lib/Transforms/Utils/SimplifyInstructions.cpp index c62aa663f6..33b3637802 100644 --- a/lib/Transforms/Utils/SimplifyInstructions.cpp +++ b/lib/Transforms/Utils/SimplifyInstructions.cpp @@ -76,7 +76,15 @@ namespace { ++NumSimplified; Changed = true; } - Changed |= RecursivelyDeleteTriviallyDeadInstructions(I, TLI); + bool res = RecursivelyDeleteTriviallyDeadInstructions(I, TLI); + if (res) { + // RecursivelyDeleteTriviallyDeadInstruction can remove + // more than one instruction, so simply incrementing the + // iterator does not work. When instructions get deleted + // re-iterate instead. + BI = BB->begin(); BE = BB->end(); + Changed |= res; + } } // Place the list of instructions to simplify on the next loop iteration diff --git a/test/Transforms/InstSimplify/dead-code-removal.ll b/test/Transforms/InstSimplify/dead-code-removal.ll new file mode 100644 index 0000000000..e181f3b60d --- /dev/null +++ b/test/Transforms/InstSimplify/dead-code-removal.ll @@ -0,0 +1,15 @@ +; RUN: opt -instsimplify -S < %s | FileCheck %s + +define void @foo() nounwind { + br i1 undef, label %1, label %4 + +; <label>:1 ; preds = %1, %0 +; CHECK-NOT: phi +; CHECK-NOT: sub + %2 = phi i32 [ %3, %1 ], [ undef, %0 ] + %3 = sub i32 0, undef + br label %1 + +; <label>:4 ; preds = %0 + ret void +} |