diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/GuardWidening.cpp | 6 | ||||
| -rw-r--r-- | llvm/test/Transforms/GuardWidening/basic.ll | 26 |
2 files changed, 32 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/GuardWidening.cpp b/llvm/lib/Transforms/Scalar/GuardWidening.cpp index 9467e5ed651..68be46ec07b 100644 --- a/llvm/lib/Transforms/Scalar/GuardWidening.cpp +++ b/llvm/lib/Transforms/Scalar/GuardWidening.cpp @@ -347,6 +347,12 @@ bool GuardWideningImpl::eliminateGuardViaWidening( Instruction *GuardInst, const df_iterator<DomTreeNode *> &DFSI, const DenseMap<BasicBlock *, SmallVector<Instruction *, 8>> & GuardsInBlock, bool InvertCondition) { + // Ignore trivial true or false conditions. These instructions will be + // trivially eliminated by any cleanup pass. Do not erase them because other + // guards can possibly be widened into them. + if (isa<ConstantInt>(getCondition(GuardInst))) + return false; + Instruction *BestSoFar = nullptr; auto BestScoreSoFar = WS_IllegalOrNegative; auto *GuardInstLoop = LI.getLoopFor(GuardInst->getParent()); diff --git a/llvm/test/Transforms/GuardWidening/basic.ll b/llvm/test/Transforms/GuardWidening/basic.ll index 5b746a5d7dd..ab18ed7362a 100644 --- a/llvm/test/Transforms/GuardWidening/basic.ll +++ b/llvm/test/Transforms/GuardWidening/basic.ll @@ -379,3 +379,29 @@ left: right: ret void } + +; Make sure we do not widen guard by trivial true conditions into something. +define void @f_15(i1 %cond_0, i1 %cond_1) { +; CHECK-LABEL: @f_15( +entry: +; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ] +; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ] +; CHECK: ret void + + call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ] + call void(i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ] + ret void +} + +; Make sure we do not widen guard by trivial false conditions into something. +define void @f_16(i1 %cond_0, i1 %cond_1) { +; CHECK-LABEL: @f_16( +entry: +; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ] +; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 false) [ "deopt"() ] +; CHECK: ret void + + call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ] + call void(i1, ...) @llvm.experimental.guard(i1 false) [ "deopt"() ] + ret void +} |
