From df772f257fb79ee3da40df0c18051163e738707d Mon Sep 17 00:00:00 2001 From: Nick Lewycky Date: Sun, 15 Nov 2009 05:55:17 +0000 Subject: Teach instcombine to look for booleans in wider integers when it encounters a zext(icmp). It may be able to optimize that away. This fixes one of the cases in PR5438. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88830 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Transforms/InstCombine/compare-signs.ll | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 test/Transforms/InstCombine/compare-signs.ll (limited to 'test/Transforms/InstCombine/compare-signs.ll') diff --git a/test/Transforms/InstCombine/compare-signs.ll b/test/Transforms/InstCombine/compare-signs.ll new file mode 100644 index 0000000..991020a --- /dev/null +++ b/test/Transforms/InstCombine/compare-signs.ll @@ -0,0 +1,28 @@ +; RUN: opt %S -instcombine -S | FileCheck %S +; PR5438 + +; TODO: This should also optimize down. +;define i32 @bar(i32 %a, i32 %b) nounwind readnone { +;entry: +; %0 = icmp sgt i32 %a, -1 ; [#uses=1] +; %1 = icmp slt i32 %b, 0 ; [#uses=1] +; %2 = xor i1 %1, %0 ; [#uses=1] +; %3 = zext i1 %2 to i32 ; [#uses=1] +; ret i32 %3 +;} + +define i32 @qaz(i32 %a, i32 %b) nounwind readnone { +; CHECK: @qaz +entry: +; CHECK: xor i32 %a, %b +; CHECK; lshr i32 %0, 31 +; CHECK: xor i32 %1, 1 + %0 = lshr i32 %a, 31 ; [#uses=1] + %1 = lshr i32 %b, 31 ; [#uses=1] + %2 = icmp eq i32 %0, %1 ; [#uses=1] + %3 = zext i1 %2 to i32 ; [#uses=1] + ret i32 %3 +; CHECK-NOT: icmp +; CHECK-NOT: zext +; CHECK: ret i32 %2 +} -- cgit v1.1