[compiler-rt] 370880c - [InstCombine] Fold icmp into phi beyond the same BB.
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llvm-commits at lists.llvm.org
Thu Sep 7 08:55:17 PDT 2023
Author: bipmis
Date: 2023-09-07T16:53:29+01:00
New Revision: 370880cdcc487298fd30628cad1a3671ba1c5f5c
URL: https://github.com/llvm/llvm-project/commit/370880cdcc487298fd30628cad1a3671ba1c5f5c
DIFF: https://github.com/llvm/llvm-project/commit/370880cdcc487298fd30628cad1a3671ba1c5f5c.diff
LOG: [InstCombine] Fold icmp into phi beyond the same BB.
The icmp is being folded in phi only if they belong in the same BB.
This patch extends the same beyond the BB.
Have seen scenarios where this seems to be beneficial.
Differential Revision: https://reviews.llvm.org/D157740
Added:
Modified:
compiler-rt/test/dfsan/conditional_callbacks.c
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/test/Transforms/InstCombine/icmp-constant-phi.ll
llvm/test/Transforms/InstCombine/phi.ll
Removed:
################################################################################
diff --git a/compiler-rt/test/dfsan/conditional_callbacks.c b/compiler-rt/test/dfsan/conditional_callbacks.c
index 3059932ec253b0..0183f0acc5dc6b 100644
--- a/compiler-rt/test/dfsan/conditional_callbacks.c
+++ b/compiler-rt/test/dfsan/conditional_callbacks.c
@@ -80,7 +80,8 @@ int main(int Argc, char *Argv[]) {
if (DataI) {
result = 42;
}
-
+
+ fprintf(stderr, "Result is %d\n", result);
assert(dfsan_get_label(DataJ) == LabelJ);
// CHECK: Label 2 used as condition
@@ -96,11 +97,13 @@ int main(int Argc, char *Argv[]) {
}
int tainted_cond = ((DataI * DataJ) != 1);
+ fprintf(stderr, "Result is %d\n", result);
assert(dfsan_get_label(tainted_cond) == LabelIJ);
// CHECK: Label 3 used as condition
result = tainted_cond ? result + 420000 : 9;
+ fprintf(stderr, "Result is %d\n", result);
assert(result == 424242);
return 0;
}
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 6091dd31d45ba0..9fdc46fec63167 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -3893,12 +3893,8 @@ Instruction *InstCombinerImpl::foldICmpInstWithConstantNotInt(ICmpInst &I) {
Constant::getNullValue(LHSI->getOperand(0)->getType()));
break;
case Instruction::PHI:
- // Only fold icmp into the PHI if the phi and icmp are in the same
- // block. If in the same block, we're encouraging jump threading. If
- // not, we are just pessimizing the code by making an i1 phi.
- if (LHSI->getParent() == I.getParent())
- if (Instruction *NV = foldOpIntoPhi(I, cast<PHINode>(LHSI)))
- return NV;
+ if (Instruction *NV = foldOpIntoPhi(I, cast<PHINode>(LHSI)))
+ return NV;
break;
case Instruction::IntToPtr:
// icmp pred inttoptr(X), null -> icmp pred X, 0
@@ -7576,12 +7572,8 @@ Instruction *InstCombinerImpl::visitFCmpInst(FCmpInst &I) {
if (match(Op0, m_Instruction(LHSI)) && match(Op1, m_Constant(RHSC))) {
switch (LHSI->getOpcode()) {
case Instruction::PHI:
- // Only fold fcmp into the PHI if the phi and fcmp are in the same
- // block. If in the same block, we're encouraging jump threading. If
- // not, we are just pessimizing the code by making an i1 phi.
- if (LHSI->getParent() == I.getParent())
- if (Instruction *NV = foldOpIntoPhi(I, cast<PHINode>(LHSI)))
- return NV;
+ if (Instruction *NV = foldOpIntoPhi(I, cast<PHINode>(LHSI)))
+ return NV;
break;
case Instruction::SIToFP:
case Instruction::UIToFP:
diff --git a/llvm/test/Transforms/InstCombine/icmp-constant-phi.ll b/llvm/test/Transforms/InstCombine/icmp-constant-phi.ll
index 95e1af4e7ee52d..7d5b3f60443d9f 100644
--- a/llvm/test/Transforms/InstCombine/icmp-constant-phi.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-constant-phi.ll
@@ -199,11 +199,9 @@ define i1 @test_ne_float(i1 %cond) {
; CHECK: if.false:
; CHECK-NEXT: br label [[MERGE]]
; CHECK: merge:
-; CHECK-NEXT: [[PHI:%.*]] = phi float [ 1.000000e+00, [[IF_TRUE]] ], [ 1.250000e+00, [[IF_FALSE]] ]
; CHECK-NEXT: br label [[EXIT:%.*]]
; CHECK: exit:
-; CHECK-NEXT: [[COMPARE:%.*]] = fcmp one float [[PHI]], 1.250000e+00
-; CHECK-NEXT: ret i1 [[COMPARE]]
+; CHECK-NEXT: ret i1 [[COND]]
;
entry:
br i1 %cond, label %if.true, label %if.false
@@ -263,11 +261,10 @@ define <2 x i1> @test_ne_float_vector(i1 %cond) {
; CHECK: if.false:
; CHECK-NEXT: br label [[MERGE]]
; CHECK: merge:
-; CHECK-NEXT: [[PHI:%.*]] = phi <2 x float> [ <float 1.232500e+02, float 1.232500e+02>, [[IF_TRUE]] ], [ <float 4.562500e+02, float 4.562500e+02>, [[IF_FALSE]] ]
+; CHECK-NEXT: [[PHI:%.*]] = phi <2 x i1> [ <i1 false, i1 true>, [[IF_TRUE]] ], [ <i1 true, i1 false>, [[IF_FALSE]] ]
; CHECK-NEXT: br label [[EXIT:%.*]]
; CHECK: exit:
-; CHECK-NEXT: [[COMPARE:%.*]] = fcmp one <2 x float> [[PHI]], <float 1.232500e+02, float 4.562500e+02>
-; CHECK-NEXT: ret <2 x i1> [[COMPARE]]
+; CHECK-NEXT: ret <2 x i1> [[PHI]]
;
entry:
br i1 %cond, label %if.true, label %if.false
diff --git a/llvm/test/Transforms/InstCombine/phi.ll b/llvm/test/Transforms/InstCombine/phi.ll
index 5344023f8a31b8..6535319b943442 100644
--- a/llvm/test/Transforms/InstCombine/phi.ll
+++ b/llvm/test/Transforms/InstCombine/phi.ll
@@ -2304,27 +2304,24 @@ define i1 @icmp_fold_into_phi_beyondBB(ptr noundef %val1, ptr noundef readonly %
; CHECK-NEXT: [[INCDEC_PTR_I]] = getelementptr inbounds i8, ptr [[TEST_0_I]], i64 1
; CHECK-NEXT: br i1 [[CMP1_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
; CHECK: while.end.i:
-; CHECK-NEXT: [[SUB_PTR_LHS_CAST_I:%.*]] = ptrtoint ptr [[TEST_0_I]] to i64
-; CHECK-NEXT: [[SUB_PTR_RHS_CAST_I:%.*]] = ptrtoint ptr [[VAL1]] to i64
-; CHECK-NEXT: [[SUB_PTR_SUB_I:%.*]] = sub i64 [[SUB_PTR_LHS_CAST_I]], [[SUB_PTR_RHS_CAST_I]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ne ptr [[TEST_0_I]], [[VAL1]]
; CHECK-NEXT: br label [[_Z3FOOPKC_EXIT]]
; CHECK: _Z3fooPKc.exit:
-; CHECK-NEXT: [[RETVAL_0_I:%.*]] = phi i64 [ [[SUB_PTR_SUB_I]], [[WHILE_END_I]] ], [ 0, [[ENTRY]] ]
+; CHECK-NEXT: [[RETVAL_0_I:%.*]] = phi i1 [ [[TMP1]], [[WHILE_END_I]] ], [ false, [[ENTRY]] ]
; CHECK-NEXT: [[CMP_I10:%.*]] = icmp eq ptr [[VAL2:%.*]], null
; CHECK-NEXT: br i1 [[CMP_I10]], label [[_Z3FOOPKC_EXIT20:%.*]], label [[WHILE_COND_I11:%.*]]
; CHECK: while.cond.i11:
; CHECK-NEXT: [[TEST_0_I12:%.*]] = phi ptr [ [[INCDEC_PTR_I14:%.*]], [[WHILE_COND_I11]] ], [ [[VAL2]], [[_Z3FOOPKC_EXIT]] ]
-; CHECK-NEXT: [[TMP1:%.*]] = load i8, ptr [[TEST_0_I12]], align 1
-; CHECK-NEXT: [[CMP1_NOT_I13:%.*]] = icmp eq i8 [[TMP1]], 0
+; CHECK-NEXT: [[TMP2:%.*]] = load i8, ptr [[TEST_0_I12]], align 1
+; CHECK-NEXT: [[CMP1_NOT_I13:%.*]] = icmp eq i8 [[TMP2]], 0
; CHECK-NEXT: [[INCDEC_PTR_I14]] = getelementptr inbounds i8, ptr [[TEST_0_I12]], i64 1
; CHECK-NEXT: br i1 [[CMP1_NOT_I13]], label [[WHILE_END_I15:%.*]], label [[WHILE_COND_I11]]
; CHECK: while.end.i15:
-; CHECK-NEXT: [[TMP2:%.*]] = icmp ne ptr [[TEST_0_I12]], [[VAL2]]
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ne ptr [[TEST_0_I12]], [[VAL2]]
; CHECK-NEXT: br label [[_Z3FOOPKC_EXIT20]]
; CHECK: _Z3fooPKc.exit20:
-; CHECK-NEXT: [[RETVAL_0_I19:%.*]] = phi i1 [ [[TMP2]], [[WHILE_END_I15]] ], [ false, [[_Z3FOOPKC_EXIT]] ]
-; CHECK-NEXT: [[TOBOOL:%.*]] = icmp ne i64 [[RETVAL_0_I]], 0
-; CHECK-NEXT: [[AND9:%.*]] = and i1 [[TOBOOL]], [[RETVAL_0_I19]]
+; CHECK-NEXT: [[RETVAL_0_I19:%.*]] = phi i1 [ [[TMP3]], [[WHILE_END_I15]] ], [ false, [[_Z3FOOPKC_EXIT]] ]
+; CHECK-NEXT: [[AND9:%.*]] = and i1 [[RETVAL_0_I]], [[RETVAL_0_I19]]
; CHECK-NEXT: ret i1 [[AND9]]
;
entry:
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