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llvm-mirror/test/Transforms/InstCombine/gepphigep.ll
Silviu Baranga 8fa79f5d2b [InstCombine] Teach instcombine not to create extra PHI nodes when folding GEPs
Summary:
InstCombine tries to transform GEP(PHI(GEP1, GEP2, ..)) into GEP(GEP(PHI(...))
when possible. However, this may leave the old PHI node around. Even if we
do end up folding the GEPs, having an extra PHI node might not be beneficial.

This change makes the transformation more conservative. We now only do this if
the PHI has only one use, and can therefore be removed after the transformation.

Reviewers: jmolloy, majnemer

Subscribers: mcrosier, mssimpso, llvm-commits

Differential Revision: http://reviews.llvm.org/D13887

llvm-svn: 251281
2015-10-26 10:25:05 +00:00

187 lines
6.1 KiB
LLVM

; RUN: opt -instcombine -S < %s | FileCheck %s
%struct1 = type { %struct2*, i32, i32, i32 }
%struct2 = type { i32, i32 }
%struct3 = type { i32, %struct4, %struct4 }
%struct4 = type { %struct2, %struct2 }
define i32 @test1(%struct1* %dm, i1 %tmp4, i64 %tmp9, i64 %tmp19) {
bb:
%tmp = getelementptr inbounds %struct1, %struct1* %dm, i64 0, i32 0
%tmp1 = load %struct2*, %struct2** %tmp, align 8
br i1 %tmp4, label %bb1, label %bb2
bb1:
%tmp10 = getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp9
%tmp11 = getelementptr inbounds %struct2, %struct2* %tmp10, i64 0, i32 0
store i32 0, i32* %tmp11, align 4
br label %bb3
bb2:
%tmp20 = getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp19
%tmp21 = getelementptr inbounds %struct2, %struct2* %tmp20, i64 0, i32 0
store i32 0, i32* %tmp21, align 4
br label %bb3
bb3:
%phi = phi %struct2* [ %tmp10, %bb1 ], [ %tmp20, %bb2 ]
%tmp24 = getelementptr inbounds %struct2, %struct2* %phi, i64 0, i32 1
%tmp25 = load i32, i32* %tmp24, align 4
ret i32 %tmp25
; CHECK-LABEL: @test1(
; CHECK: getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp9, i32 0
; CHECK: getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp19, i32 0
; CHECK: %[[PHI:[0-9A-Za-z]+]] = phi i64 [ %tmp9, %bb1 ], [ %tmp19, %bb2 ]
; CHECK: getelementptr inbounds %struct2, %struct2* %tmp1, i64 %[[PHI]], i32 1
}
define i32 @test2(%struct1* %dm, i1 %tmp4, i64 %tmp9, i64 %tmp19) {
bb:
%tmp = getelementptr inbounds %struct1, %struct1* %dm, i64 0, i32 0
%tmp1 = load %struct2*, %struct2** %tmp, align 8
%tmp10 = getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp9
%tmp11 = getelementptr inbounds %struct2, %struct2* %tmp10, i64 0, i32 0
store i32 0, i32* %tmp11, align 4
%tmp20 = getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp19
%tmp21 = getelementptr inbounds %struct2, %struct2* %tmp20, i64 0, i32 0
store i32 0, i32* %tmp21, align 4
%tmp24 = getelementptr inbounds %struct2, %struct2* %tmp10, i64 0, i32 1
%tmp25 = load i32, i32* %tmp24, align 4
ret i32 %tmp25
; CHECK-LABEL: @test2(
; CHECK: getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp9, i32 0
; CHECK: getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp19, i32 0
; CHECK: getelementptr inbounds %struct2, %struct2* %tmp1, i64 %tmp9, i32 1
}
; Check that instcombine doesn't insert GEPs before landingpad.
define i32 @test3(%struct3* %dm, i1 %tmp4, i64 %tmp9, i64 %tmp19, i64 %tmp20, i64 %tmp21) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
bb:
%tmp = getelementptr inbounds %struct3, %struct3* %dm, i64 0
br i1 %tmp4, label %bb1, label %bb2
bb1:
%tmp1 = getelementptr inbounds %struct3, %struct3* %tmp, i64 %tmp19, i32 1
%tmp11 = getelementptr inbounds %struct4, %struct4* %tmp1, i64 0, i32 0, i32 0
store i32 0, i32* %tmp11, align 4
br label %bb3
bb2:
%tmp2 = getelementptr inbounds %struct3, %struct3* %tmp, i64 %tmp20, i32 1
%tmp12 = getelementptr inbounds %struct4, %struct4* %tmp2, i64 0, i32 0, i32 1
store i32 0, i32* %tmp12, align 4
br label %bb3
bb3:
%phi = phi %struct4* [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
%tmp22 = invoke i32 @foo1(i32 11) to label %bb4 unwind label %bb5
bb4:
ret i32 0
bb5:
%tmp27 = landingpad { i8*, i32 } catch i8* bitcast (i8** @_ZTIi to i8*)
%tmp34 = getelementptr inbounds %struct4, %struct4* %phi, i64 %tmp21, i32 1
%tmp35 = getelementptr inbounds %struct2, %struct2* %tmp34, i64 0, i32 1
%tmp25 = load i32, i32* %tmp35, align 4
ret i32 %tmp25
; CHECK-LABEL: @test3(
; CHECK: bb5:
; CHECK-NEXT: {{.*}}landingpad { i8*, i32 }
}
@_ZTIi = external constant i8*
declare i32 @__gxx_personality_v0(...)
declare i32 @foo1(i32)
; Check that instcombine doesn't fold GEPs into themselves through a loop
; back-edge.
define i8* @test4(i32 %value, i8* %buffer) {
entry:
%incptr = getelementptr inbounds i8, i8* %buffer, i64 1
%cmp = icmp ugt i32 %value, 127
br i1 %cmp, label %loop.header, label %exit
loop.header:
br label %loop.body
loop.body:
%loopptr = phi i8* [ %incptr, %loop.header ], [ %incptr2, %loop.body ]
%newval = phi i32 [ %value, %loop.header ], [ %shr, %loop.body ]
%shr = lshr i32 %newval, 7
%incptr2 = getelementptr inbounds i8, i8* %loopptr, i64 1
%cmp2 = icmp ugt i32 %shr, 127
br i1 %cmp2, label %loop.body, label %loop.exit
loop.exit:
%exitptr = phi i8* [ %incptr2, %loop.body ]
br label %exit
exit:
%ptr2 = phi i8* [ %exitptr, %loop.exit ], [ %incptr, %entry ]
%incptr3 = getelementptr inbounds i8, i8* %ptr2, i64 1
ret i8* %incptr3
; CHECK-LABEL: @test4(
; CHECK: loop.body:
; CHECK: getelementptr{{.*}}i64 1
; CHECK: exit:
}
@.str.4 = external unnamed_addr constant [100 x i8], align 1
; Instcombine shouldn't add new PHI nodes while folding GEPs if that will leave
; old PHI nodes behind as this is not clearly beneficial.
; CHECK-LABEL: @test5(
define void @test5(i16 *%idx, i8 **%in) #0 {
entry:
%0 = load i8*, i8** %in
%incdec.ptr = getelementptr inbounds i8, i8* %0, i32 1
%1 = load i8, i8* %incdec.ptr, align 1
%cmp23 = icmp eq i8 %1, 54
br i1 %cmp23, label %while.cond, label %if.then.25
if.then.25:
call void @g(i8* getelementptr inbounds ([100 x i8], [100 x i8]* @.str.4, i32 0, i32 0))
br label %while.cond
while.cond:
; CHECK-LABEL: while.cond
; CHECK-NOT: phi i8* [ %0, %entry ], [ %Ptr, %while.body ], [ %0, %if.then.25 ]
%Ptr = phi i8* [ %incdec.ptr, %entry ], [ %incdec.ptr32, %while.body], [%incdec.ptr, %if.then.25 ]
%2 = load i8, i8* %Ptr
%and = and i8 %2, 64
%lnot = icmp eq i8 %and, 0
br i1 %lnot, label %while.body, label %while.cond.33
while.body:
%incdec.ptr32 = getelementptr inbounds i8, i8* %Ptr, i32 1
br label %while.cond
while.cond.33:
%incdec.ptr34 = getelementptr inbounds i8, i8* %Ptr, i32 1
br label %while.cond.57
while.cond.57:
%3 = load i8, i8* %incdec.ptr34, align 1
%conv59 = zext i8 %3 to i32
%arrayidx61 = getelementptr inbounds i16, i16* %idx, i32 %conv59
%4 = load i16, i16* %arrayidx61, align 2
%and63 = and i16 %4, 2048
%tobool64 = icmp eq i16 %and63, 0
br i1 %tobool64, label %while.cond.73, label %while.cond.57
while.cond.73:
br label %while.cond.73
}
declare void @g(i8*)