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[DAGCombiner] Do not remove the load of stored values when optimizations are disabled 

This combiner breaks debug experience and should not be run when optimizations are disabled.

For example:
  int main() {
    int j = 0;
    j += 2;
    if (j == 2)
      return 0;
    return 5;
  }
When debugging this code compiled in /O0, it should be valid to break at line "j+=2;" and edit the value of j. It should change the return value of the function.

Differential Revision: https://reviews.llvm.org/D19268

llvm-svn: 284014
This commit is contained in:
Konstantin Zhuravlyov 2016-10-12 13:44:24 +00:00
parent c215c3fd14
commit 081385a74e
6 changed files with 54 additions and 9 deletions
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3
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -10196,7 +10196,8 @@ SDValue DAGCombiner::visitLOAD(SDNode *N) {
// value.
// TODO: Handle store large -> read small portion.
// TODO: Handle TRUNCSTORE/LOADEXT
if (ISD::isNormalLoad(N) && !LD->isVolatile()) {
if (OptLevel != CodeGenOpt::None &&
ISD::isNormalLoad(N) && !LD->isVolatile()) {
if (ISD::isNON_TRUNCStore(Chain.getNode())) {
StoreSDNode *PrevST = cast<StoreSDNode>(Chain);
if (PrevST->getBasePtr() == Ptr &&

5
llvm/test/CodeGen/ARM/alloc-no-stack-realign.ll
View File

@ -21,8 +21,9 @@ entry:
; NO-REALIGN: vst1.64 {{{d[0-9]+, d[0-9]+}}}, [r[[R2]]:128]
; NO-REALIGN: add r[[R2:[0-9]+]], r[[R1]], #32
; NO-REALIGN: vst1.64 {{{d[0-9]+, d[0-9]+}}}, [r[[R2]]:128]
; NO-REALIGN: vst1.32 {{{d[0-9]+, d[0-9]+}}}, [r[[R1]]:128]!
; NO-REALIGN: vst1.64 {{{d[0-9]+, d[0-9]+}}}, [r[[R1]]:128]
; NO-REALIGN: mov r[[R3:[0-9]+]], r[[R1]]
; NO-REALIGN: vst1.32 {{{d[0-9]+, d[0-9]+}}}, [r[[R3]]:128]!
; NO-REALIGN: vst1.64 {{{d[0-9]+, d[0-9]+}}}, [r[[R3]]:128]
; NO-REALIGN: add r[[R2:[0-9]+]], r[[R0:0]], #48
; NO-REALIGN: vst1.64 {{{d[0-9]+, d[0-9]+}}}, [r[[R2]]:128]

41
llvm/test/CodeGen/ARM/dag-combine-ldst.ll Normal file
View File

@ -0,0 +1,41 @@
; RUN: llc < %s -mtriple=arm-eabi -mattr=+v4t -O0 | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK_O0
; RUN: llc < %s -mtriple=arm-eabi -mattr=+v4t -O1 | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK_O1
; In /O0, the addition must not be eliminated. This happens when the load
; and store are folded by the DAGCombiner. In /O1 and above, the optimization
; must be executed.
; CHECK-LABEL: {{^}}main
; CHECK: mov [[TMP:r[0-9]+]], #0
; CHECK-NEXT: str [[TMP]], [sp, #4]
; CHECK-NEXT: str [[TMP]], [sp]
; CHECK_O0: ldr [[TMP:r[0-9]+]], [sp]
; CHECK_O0-NEXT: add [[TMP]], [[TMP]], #2
; CHECK_O1-NOT: ldr [[TMP:r[0-9]+]], [sp]
; CHECK_O1-NOT: add [[TMP]], [[TMP]], #2
define i32 @main() {
bb:
%tmp = alloca i32, align 4
%tmp1 = alloca i32, align 4
store i32 0, i32* %tmp, align 4
store i32 0, i32* %tmp1, align 4
%tmp2 = load i32, i32* %tmp1, align 4
%tmp3 = add nsw i32 %tmp2, 2
store i32 %tmp3, i32* %tmp1, align 4
%tmp4 = load i32, i32* %tmp1, align 4
%tmp5 = icmp eq i32 %tmp4, 2
br i1 %tmp5, label %bb6, label %bb7
bb6: ; preds = %bb
store i32 0, i32* %tmp, align 4
br label %bb8
bb7: ; preds = %bb
store i32 5, i32* %tmp, align 4
br label %bb8
bb8: ; preds = %bb7, %bb6
%tmp9 = load i32, i32* %tmp, align 4
ret i32 %tmp9
}

3
llvm/test/CodeGen/SystemZ/swift-return.ll
View File

@ -49,10 +49,9 @@ declare swiftcc { i16, i8 } @gen(i32)
; CHECK: a %r2, 172(%r15)
; CHECK: a %r2, 176(%r15)
; CHECK-O0-LABEL: test2:
; CHECK-O0: la %[[REG1:r[0-9]+]], 168(%r15)
; CHECK-O0: st %r2, [[SPILL1:[0-9]+]](%r15)
; CHECK-O0: lgr %r2, %[[REG1]]
; CHECK-O0: l %r3, [[SPILL1]](%r15)
; CHECK-O0: la %r2, 168(%r15)
; CHECK-O0: brasl %r14, gen2
; CHECK-O0-DAG: l %r{{.*}}, 184(%r15)
; CHECK-O0-DAG: l %r{{.*}}, 180(%r15)

5
llvm/test/CodeGen/X86/inline-asm-tied.ll
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@ -1,8 +1,9 @@
; RUN: llc < %s -mtriple=i386-apple-darwin9 -O0 -optimize-regalloc -regalloc=basic -no-integrated-as | FileCheck %s
; rdar://6992609
; CHECK: movl [[EDX:%e..]], 4(%esp)
; CHECK: movl [[EDX]], 4(%esp)
; CHECK: movl %ecx, 4([[ESP:%e..]])
; CHECK: movl 4([[ESP]]), [[EDX:%e..]]
; CHECK: movl [[EDX]], 4([[ESP]])
target triple = "i386-apple-darwin9.0"
@llvm.used = appending global [1 x i8*] [i8* bitcast (i64 (i64)* @_OSSwapInt64 to i8*)], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]

6
llvm/test/CodeGen/X86/pr30430.ll
View File

@ -46,6 +46,7 @@ define <16 x float> @makefloat(float %f1, float %f2, float %f3, float %f4, float
; CHECK-NEXT: vmovss {{.*#+}} xmm5 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss {{.*#+}} xmm6 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss {{.*#+}} xmm7 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss {{.*#+}} xmm8 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss {{.*#+}} xmm9 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss {{.*#+}} xmm10 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss {{.*#+}} xmm11 = mem[0],zero,zero,zero
@ -53,7 +54,6 @@ define <16 x float> @makefloat(float %f1, float %f2, float %f3, float %f4, float
; CHECK-NEXT: vmovss {{.*#+}} xmm13 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss {{.*#+}} xmm14 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss {{.*#+}} xmm15 = mem[0],zero,zero,zero
; CHECK-NEXT: vmovss %xmm8, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm0, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm1, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm2, {{[0-9]+}}(%rsp)
@ -62,6 +62,7 @@ define <16 x float> @makefloat(float %f1, float %f2, float %f3, float %f4, float
; CHECK-NEXT: vmovss %xmm5, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm6, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm7, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm8, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm9, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm10, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovss %xmm11, {{[0-9]+}}(%rsp)
@ -94,7 +95,8 @@ define <16 x float> @makefloat(float %f1, float %f2, float %f3, float %f4, float
; CHECK-NEXT: vmovss {{.*#+}} xmm1 = mem[0],zero,zero,zero
; CHECK-NEXT: vinsertps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[0]
; CHECK-NEXT: vmovss {{.*#+}} xmm1 = mem[0],zero,zero,zero
; CHECK-NEXT: vinsertps {{.*#+}} xmm1 = xmm15[0],xmm1[0],xmm15[2,3]
; CHECK-NEXT: vmovss {{.*#+}} xmm3 = mem[0],zero,zero,zero
; CHECK-NEXT: vinsertps {{.*#+}} xmm1 = xmm3[0],xmm1[0],xmm3[2,3]
; CHECK-NEXT: vmovss {{.*#+}} xmm3 = mem[0],zero,zero,zero
; CHECK-NEXT: vinsertps {{.*#+}} xmm1 = xmm1[0,1],xmm3[0],xmm1[3]
; CHECK-NEXT: vmovss {{.*#+}} xmm3 = mem[0],zero,zero,zero