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https://github.com/c64scene-ar/llvm-6502.git
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2d1fa5f718
Currently LLVM will generally merge GEPs. This allows backends to use more
complex addressing modes. In some cases this is not happening because there
is PHI inbetween the two GEPs:
GEP1--\
|-->PHI1-->GEP3
GEP2--/
This patch checks to see if GEP1 and GEP2 are similiar enough that they can be
cloned (GEP12) in GEP3's BB, allowing GEP->GEP merging (GEP123):
GEP1--\ --\ --\
|-->PHI1-->GEP3 ==> |-->PHI2->GEP12->GEP3 == > |-->PHI2->GEP123
GEP2--/ --/ --/
This also breaks certain use chains that are preventing GEP->GEP merges that the
the existing instcombine would merge otherwise.
Tests included.
rdar://15547484
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209049 91177308-0d34-0410-b5e6-96231b3b80d8
57 lines
2.0 KiB
LLVM
57 lines
2.0 KiB
LLVM
; RUN: opt -instcombine -S < %s | FileCheck %s
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%struct1 = type { %struct2*, i32, i32, i32 }
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%struct2 = type { i32, i32 }
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define i32 @test1(%struct1* %dm, i1 %tmp4, i64 %tmp9, i64 %tmp19) {
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bb:
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%tmp = getelementptr inbounds %struct1* %dm, i64 0, i32 0
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%tmp1 = load %struct2** %tmp, align 8
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br i1 %tmp4, label %bb1, label %bb2
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bb1:
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%tmp10 = getelementptr inbounds %struct2* %tmp1, i64 %tmp9
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%tmp11 = getelementptr inbounds %struct2* %tmp10, i64 0, i32 0
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store i32 0, i32* %tmp11, align 4
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br label %bb3
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bb2:
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%tmp20 = getelementptr inbounds %struct2* %tmp1, i64 %tmp19
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%tmp21 = getelementptr inbounds %struct2* %tmp20, i64 0, i32 0
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store i32 0, i32* %tmp21, align 4
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br label %bb3
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bb3:
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%phi = phi %struct2* [ %tmp10, %bb1 ], [ %tmp20, %bb2 ]
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%tmp24 = getelementptr inbounds %struct2* %phi, i64 0, i32 1
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%tmp25 = load i32* %tmp24, align 4
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ret i32 %tmp25
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; CHECK-LABEL: @test1(
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; CHECK: getelementptr inbounds %struct2* %tmp1, i64 %tmp9, i32 0
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; CHECK: getelementptr inbounds %struct2* %tmp1, i64 %tmp19, i32 0
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; CHECK: %[[PHI:[0-9A-Za-z]+]] = phi i64 [ %tmp9, %bb1 ], [ %tmp19, %bb2 ]
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; CHECK: getelementptr inbounds %struct2* %tmp1, i64 %[[PHI]], i32 1
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}
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define i32 @test2(%struct1* %dm, i1 %tmp4, i64 %tmp9, i64 %tmp19) {
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bb:
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%tmp = getelementptr inbounds %struct1* %dm, i64 0, i32 0
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%tmp1 = load %struct2** %tmp, align 8
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%tmp10 = getelementptr inbounds %struct2* %tmp1, i64 %tmp9
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%tmp11 = getelementptr inbounds %struct2* %tmp10, i64 0, i32 0
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store i32 0, i32* %tmp11, align 4
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%tmp20 = getelementptr inbounds %struct2* %tmp1, i64 %tmp19
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%tmp21 = getelementptr inbounds %struct2* %tmp20, i64 0, i32 0
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store i32 0, i32* %tmp21, align 4
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%tmp24 = getelementptr inbounds %struct2* %tmp10, i64 0, i32 1
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%tmp25 = load i32* %tmp24, align 4
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ret i32 %tmp25
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; CHECK-LABEL: @test2(
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; CHECK: getelementptr inbounds %struct2* %tmp1, i64 %tmp9, i32 0
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; CHECK: getelementptr inbounds %struct2* %tmp1, i64 %tmp19, i32 0
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; CHECK: getelementptr inbounds %struct2* %tmp1, i64 %tmp9, i32 1
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}
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