From d1ec98923e2eee1fb4e6cd1f91b80210f021e301 Mon Sep 17 00:00:00 2001 From: Nick Lewycky Date: Sat, 4 Jul 2009 17:24:52 +0000 Subject: [PATCH] When comparing constants, consider a less wide constant to be "less complex" than a wider one, before trying to compare their contents which will crash if their sizes are different. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74792 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ScalarEvolution.cpp | 2 ++ .../2009-07-04-GroupConstantsWidthMismatch.ll | 16 ++++++++++++++++ 2 files changed, 18 insertions(+) create mode 100644 test/Analysis/ScalarEvolution/2009-07-04-GroupConstantsWidthMismatch.ll diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 408156265d2..aa4b58661cc 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -495,6 +495,8 @@ namespace { // Compare constant values. if (const SCEVConstant *LC = dyn_cast(LHS)) { const SCEVConstant *RC = cast(RHS); + if (LC->getValue()->getBitWidth() != RC->getValue()->getBitWidth()) + return LC->getValue()->getBitWidth() < RC->getValue()->getBitWidth(); return LC->getValue()->getValue().ult(RC->getValue()->getValue()); } diff --git a/test/Analysis/ScalarEvolution/2009-07-04-GroupConstantsWidthMismatch.ll b/test/Analysis/ScalarEvolution/2009-07-04-GroupConstantsWidthMismatch.ll new file mode 100644 index 00000000000..b5d588e01ad --- /dev/null +++ b/test/Analysis/ScalarEvolution/2009-07-04-GroupConstantsWidthMismatch.ll @@ -0,0 +1,16 @@ +; RUN: llvm-as < %s | opt -analyze -scalar-evolution +; PR4501 + +define void @test() { +entry: + %0 = load i16* undef, align 1 + %1 = lshr i16 %0, 8 + %2 = and i16 %1, 3 + %3 = zext i16 %2 to i32 + %4 = load i8* undef, align 1 + %5 = lshr i8 %4, 4 + %6 = and i8 %5, 1 + %7 = zext i8 %6 to i32 + %t1 = add i32 %3, %7 + ret void +}