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https://github.com/c64scene-ar/llvm-6502.git
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e9cdbf68e5
This is common in bitfield code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194925 91177308-0d34-0410-b5e6-96231b3b80d8
59 lines
1.9 KiB
LLVM
59 lines
1.9 KiB
LLVM
; RUN: opt -instcombine -S < %s | FileCheck %s
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; PR5438
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; TODO: This should also optimize down.
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;define i32 @test1(i32 %a, i32 %b) nounwind readnone {
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;entry:
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; %0 = icmp sgt i32 %a, -1 ; <i1> [#uses=1]
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; %1 = icmp slt i32 %b, 0 ; <i1> [#uses=1]
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; %2 = xor i1 %1, %0 ; <i1> [#uses=1]
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; %3 = zext i1 %2 to i32 ; <i32> [#uses=1]
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; ret i32 %3
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;}
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; TODO: This optimizes partially but not all the way.
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;define i32 @test2(i32 %a, i32 %b) nounwind readnone {
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;entry:
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; %0 = and i32 %a, 8 ;<i32> [#uses=1]
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; %1 = and i32 %b, 8 ;<i32> [#uses=1]
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; %2 = icmp eq i32 %0, %1 ;<i1> [#uses=1]
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; %3 = zext i1 %2 to i32 ;<i32> [#uses=1]
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; ret i32 %3
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;}
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define i32 @test3(i32 %a, i32 %b) nounwind readnone {
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; CHECK-LABEL: @test3(
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entry:
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; CHECK: [[XOR1:%.*]] = xor i32 %a, %b
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; CHECK: [[SHIFT:%.*]] = lshr i32 [[XOR1]], 31
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; CHECK: [[XOR2:%.*]] = xor i32 [[SHIFT]], 1
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%0 = lshr i32 %a, 31 ; <i32> [#uses=1]
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%1 = lshr i32 %b, 31 ; <i32> [#uses=1]
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%2 = icmp eq i32 %0, %1 ; <i1> [#uses=1]
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%3 = zext i1 %2 to i32 ; <i32> [#uses=1]
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ret i32 %3
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; CHECK-NOT: icmp
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; CHECK-NOT: zext
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; CHECK: ret i32 [[XOR2]]
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}
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; Variation on @test3: checking the 2nd bit in a situation where the 5th bit
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; is one, not zero.
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define i32 @test3i(i32 %a, i32 %b) nounwind readnone {
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; CHECK-LABEL: @test3i(
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entry:
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; CHECK: xor i32 %a, %b
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; CHECK: lshr i32 %0, 31
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; CHECK: xor i32 %1, 1
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%0 = lshr i32 %a, 29 ; <i32> [#uses=1]
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%1 = lshr i32 %b, 29 ; <i32> [#uses=1]
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%2 = or i32 %0, 35
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%3 = or i32 %1, 35
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%4 = icmp eq i32 %2, %3 ; <i1> [#uses=1]
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%5 = zext i1 %4 to i32 ; <i32> [#uses=1]
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ret i32 %5
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; CHECK-NOT: icmp
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; CHECK-NOT: zext
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; CHECK: ret i32 %2
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}
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