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author | Gerolf Hoflehner <ghoflehner@apple.com> | 2014-04-26 01:19:16 +0000 |
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committer | Gerolf Hoflehner <ghoflehner@apple.com> | 2014-04-26 01:19:16 +0000 |
commit | 4c9277bb9fc1399aa0c845c870447ae83cdb2cb1 (patch) | |
tree | b723dacc83eb65812a1bb56837260d4b1bf2f292 | |
parent | 9e93e47b7f196893b5779090897210d750aa1c6b (diff) | |
download | llvm-4c9277bb9fc1399aa0c845c870447ae83cdb2cb1.tar.gz llvm-4c9277bb9fc1399aa0c845c870447ae83cdb2cb1.tar.bz2 llvm-4c9277bb9fc1399aa0c845c870447ae83cdb2cb1.tar.xz |
RecursivelyDeleteTriviallyDeadInstructions() could remove
more than 1 instruction. The caller need to be aware of this
and adjust instruction iterators accordingly.
rdar://16679376
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207302 91177308-0d34-0410-b5e6-96231b3b80d8
-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..89c9d9cea2 --- /dev/null +++ b/test/Transforms/InstSimplify/dead-code-removal.ll @@ -0,0 +1,15 @@ +; RUN: opts -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 +} |