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authorNick Lewycky <nicholas@mxc.ca>2009-11-15 05:55:17 +0000
committerNick Lewycky <nicholas@mxc.ca>2009-11-15 05:55:17 +0000
commitdf772f257fb79ee3da40df0c18051163e738707d (patch)
treeae879fcbe618334e8bf2a5bd144b0653cae6bb51 /test/Transforms
parente98b4b0695f727dda44c366f5de906edf06cf7e9 (diff)
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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
Diffstat (limited to 'test/Transforms')
-rw-r--r--test/Transforms/InstCombine/compare-signs.ll28
1 files changed, 28 insertions, 0 deletions
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 ; <i1> [#uses=1]
+; %1 = icmp slt i32 %b, 0 ; <i1> [#uses=1]
+; %2 = xor i1 %1, %0 ; <i1> [#uses=1]
+; %3 = zext i1 %2 to i32 ; <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 ; <i32> [#uses=1]
+ %1 = lshr i32 %b, 31 ; <i32> [#uses=1]
+ %2 = icmp eq i32 %0, %1 ; <i1> [#uses=1]
+ %3 = zext i1 %2 to i32 ; <i32> [#uses=1]
+ ret i32 %3
+; CHECK-NOT: icmp
+; CHECK-NOT: zext
+; CHECK: ret i32 %2
+}