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author | Chris Lattner <sabre@nondot.org> | 2009-12-21 04:04:05 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2009-12-21 04:04:05 +0000 |
commit | 3bf68155563cac6848d671848d875f41ad7e3277 (patch) | |
tree | 396f56075134fb3d58520cdb78c3ccbe58bf6409 /test/Transforms/InstCombine/icmp.ll | |
parent | 2799bafb98676c000388f8636d58064f2646266e (diff) | |
download | llvm-3bf68155563cac6848d671848d875f41ad7e3277.tar.gz llvm-3bf68155563cac6848d671848d875f41ad7e3277.tar.bz2 llvm-3bf68155563cac6848d671848d875f41ad7e3277.tar.xz |
enhance x-(-A) -> x+A to preserve NUW/NSW.
Use the presence of NSW/NUW to fold "icmp (x+cst), x" to a constant in
cases where it would otherwise be undefined behavior.
Surprisingly (to me at least), this triggers hundreds of the times in
a few benchmarks: lencode, ldecode, and 466.h264ref seem to *really*
like this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91812 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Transforms/InstCombine/icmp.ll')
-rw-r--r-- | test/Transforms/InstCombine/icmp.ll | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll index f469dd4ef2..79fa220752 100644 --- a/test/Transforms/InstCombine/icmp.ll +++ b/test/Transforms/InstCombine/icmp.ll @@ -69,6 +69,7 @@ entry: %a = add i32 %x, -1 %b = icmp ult i32 %a, %x ret i1 %b +; CHECK: @test7 ; CHECK: %b = icmp ne i32 %x, 0 ; CHECK: ret i1 %b } @@ -78,6 +79,7 @@ entry: %a = add i32 %x, -1 %b = icmp eq i32 %a, %x ret i1 %b +; CHECK: @test8 ; CHECK: ret i1 false } @@ -86,6 +88,7 @@ entry: %a = add i32 %x, -2 %b = icmp ugt i32 %x, %a ret i1 %b +; CHECK: @test9 ; CHECK: icmp ugt i32 %x, 1 ; CHECK: ret i1 %b } @@ -96,6 +99,16 @@ entry: %b = icmp slt i32 %a, %x ret i1 %b +; CHECK: @test10 ; CHECK: %b = icmp ne i32 %x, -2147483648 ; CHECK: ret i1 %b } + +define i1 @test11(i32 %x) { + %a = add nsw i32 %x, 8 + %b = icmp slt i32 %x, %a + ret i1 %b +; CHECK: @test11 +; CHECK: ret i1 true +} + |