diff options
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 5 | ||||
| -rw-r--r-- | test/Transforms/SimplifyCFG/phi-undef-loadstore.ll | 28 |
2 files changed, 31 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 6da791bb1c..0edf7cadc8 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -3786,11 +3786,12 @@ static bool passingValueIsAlwaysUndefined(Value *V, Instruction *I) { if (!C) return false; - if (!I->hasOneUse()) // Only look at single-use instructions, for compile time + if (I->use_empty()) return false; if (C->isNullValue()) { - Instruction *Use = I->use_back(); + // Only look at the first use, avoid hurting compile time with long uselists + User *Use = *I->use_begin(); // Now make sure that there are no instructions in between that can alter // control flow (eg. calls) diff --git a/test/Transforms/SimplifyCFG/phi-undef-loadstore.ll b/test/Transforms/SimplifyCFG/phi-undef-loadstore.ll index 65d888ea01..028fb07456 100644 --- a/test/Transforms/SimplifyCFG/phi-undef-loadstore.ll +++ b/test/Transforms/SimplifyCFG/phi-undef-loadstore.ll @@ -85,3 +85,31 @@ if.end7: ; preds = %if.else, %if.then4, ; CHECK: if.end7: ; CHECK: phi i32* [ %a, %if.then ], [ null, %if.then4 ], [ null, %if.else ] } + +define i32 @test4(i32* %a, i32 %b, i32* %c, i32 %d) nounwind { +entry: + %tobool = icmp eq i32 %b, 0 + br i1 %tobool, label %if.else, label %if.then + +if.then: ; preds = %entry + tail call void @bar() nounwind + br label %if.end7 + +if.else: ; preds = %entry + %tobool3 = icmp eq i32 %d, 0 + br i1 %tobool3, label %if.end7, label %if.then4 + +if.then4: ; preds = %if.else + tail call void @bar() nounwind + br label %if.end7 + +if.end7: ; preds = %if.else, %if.then4, %if.then + %x.0 = phi i32* [ %a, %if.then ], [ null, %if.then4 ], [ null, %if.else ] + %gep = getelementptr i32* %x.0, i32 10 + %tmp9 = load i32* %gep + %tmp10 = or i32 %tmp9, 1 + store i32 %tmp10, i32* %gep + ret i32 %tmp9 +; CHECK: @test4 +; CHECK-NOT: phi +} |