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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2013-11-16 16:00:48 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2013-11-16 16:00:48 +0000 |
| commit | e9cdbf68e542bbb79597d6233dd2a339c89862a2 (patch) | |
| tree | d38004354c7d6a76ed51ea01a8981b9abdcc1325 /test/Transforms | |
| parent | bd9f36f4db42f4b73caeb8cfe04e98f047d99375 (diff) | |
| download | external_llvm-e9cdbf68e542bbb79597d6233dd2a339c89862a2.zip external_llvm-e9cdbf68e542bbb79597d6233dd2a339c89862a2.tar.gz external_llvm-e9cdbf68e542bbb79597d6233dd2a339c89862a2.tar.bz2 | |
InstCombine: fold (A >> C) == (B >> C) --> (A^B) < (1 << C) for constant Cs.
This is common in bitfield code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194925 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Transforms')
| -rw-r--r-- | test/Transforms/InstCombine/compare-signs.ll | 8 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/icmp.ll | 28 |
2 files changed, 28 insertions, 8 deletions
diff --git a/test/Transforms/InstCombine/compare-signs.ll b/test/Transforms/InstCombine/compare-signs.ll index cdf95ab..62cd5b3 100644 --- a/test/Transforms/InstCombine/compare-signs.ll +++ b/test/Transforms/InstCombine/compare-signs.ll @@ -24,9 +24,9 @@ define i32 @test3(i32 %a, i32 %b) nounwind readnone { ; CHECK-LABEL: @test3( entry: -; CHECK: xor i32 %a, %b -; CHECK: lshr i32 %0, 31 -; CHECK: xor i32 %1, 1 +; CHECK: [[XOR1:%.*]] = xor i32 %a, %b +; CHECK: [[SHIFT:%.*]] = lshr i32 [[XOR1]], 31 +; CHECK: [[XOR2:%.*]] = xor i32 [[SHIFT]], 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] @@ -34,7 +34,7 @@ entry: ret i32 %3 ; CHECK-NOT: icmp ; CHECK-NOT: zext -; CHECK: ret i32 %2 +; CHECK: ret i32 [[XOR2]] } ; Variation on @test3: checking the 2nd bit in a situation where the 5th bit diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll index bd8128f..12a4744 100644 --- a/test/Transforms/InstCombine/icmp.ll +++ b/test/Transforms/InstCombine/icmp.ll @@ -523,12 +523,12 @@ define i1 @test52(i32 %x1) nounwind { ; PR9838 ; CHECK-LABEL: @test53( -; CHECK-NEXT: ashr exact -; CHECK-NEXT: ashr +; CHECK-NEXT: sdiv exact +; CHECK-NEXT: sdiv ; CHECK-NEXT: icmp define i1 @test53(i32 %a, i32 %b) nounwind { - %x = ashr exact i32 %a, 30 - %y = ashr i32 %b, 30 + %x = sdiv exact i32 %a, 30 + %y = sdiv i32 %b, 30 %z = icmp eq i32 %x, %y ret i1 %z } @@ -1336,3 +1336,23 @@ end: %res = phi i1 [%restrue, %true], [%resfalse, %false] ret i1 %res } + +; CHECK-LABEL: @icmp_lshr_lshr_eq +; CHECK: %z.unshifted = xor i32 %a, %b +; CHECK: %z = icmp ult i32 %z.unshifted, 1073741824 +define i1 @icmp_lshr_lshr_eq(i32 %a, i32 %b) nounwind { + %x = lshr i32 %a, 30 + %y = lshr i32 %b, 30 + %z = icmp eq i32 %x, %y + ret i1 %z +} + +; CHECK-LABEL: @icmp_ashr_ashr_ne +; CHECK: %z.unshifted = xor i32 %a, %b +; CHECK: %z = icmp ugt i32 %z.unshifted, 255 +define i1 @icmp_ashr_ashr_ne(i32 %a, i32 %b) nounwind { + %x = ashr i32 %a, 8 + %y = ashr i32 %b, 8 + %z = icmp ne i32 %x, %y + ret i1 %z +} |