diff options
| -rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 4 | ||||
| -rw-r--r-- | test/Analysis/ScalarEvolution/fold.ll | 8 |
2 files changed, 12 insertions, 0 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index b3df926119..ce04188490 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -994,6 +994,10 @@ const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op, if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op)) return getSignExtendExpr(SS->getOperand(), Ty); + // sext(zext(x)) --> zext(x) + if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op)) + return getZeroExtendExpr(SZ->getOperand(), Ty); + // Before doing any expensive analysis, check to see if we've already // computed a SCEV for this Op and Ty. FoldingSetNodeID ID; diff --git a/test/Analysis/ScalarEvolution/fold.ll b/test/Analysis/ScalarEvolution/fold.ll new file mode 100644 index 0000000000..202ddd4169 --- /dev/null +++ b/test/Analysis/ScalarEvolution/fold.ll @@ -0,0 +1,8 @@ +; RUN: opt -analyze -scalar-evolution %s -S | FileCheck %s + +define i16 @test(i8 %x) { + %A = zext i8 %x to i12 + %B = sext i12 %A to i16 +; CHECK: zext i8 %x to i16 + ret i16 %B +} |