[clang] 5bf0858 - Return "[InstCombine] Simplify compare of Phi with constant inputs against a constant"
Sam Parker via cfe-commits
cfe-commits at lists.llvm.org
Wed Jun 17 03:39:17 PDT 2020
Author: Sam Parker
Date: 2020-06-17T11:38:59+01:00
New Revision: 5bf0858c0b4cb5237fa4bf0cf58a76ec5076ef5a
URL: https://github.com/llvm/llvm-project/commit/5bf0858c0b4cb5237fa4bf0cf58a76ec5076ef5a
DIFF: https://github.com/llvm/llvm-project/commit/5bf0858c0b4cb5237fa4bf0cf58a76ec5076ef5a.diff
LOG: Return "[InstCombine] Simplify compare of Phi with constant inputs against a constant"
I originally reverted the patch because it was causing performance
issues, but now I think it's just enabling simplify-cfg to do
something that I don't want instead :)
Sorry for the noise.
This reverts commit 3e39760f8eaad4770efa05824768e67237915cf5.
Added:
Modified:
clang/test/CodeGenObjC/exceptions.m
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/test/Transforms/InstCombine/icmp-constant-phi.ll
llvm/test/Transforms/InstCombine/indexed-gep-compares.ll
llvm/test/Transforms/InstCombine/zext-or-icmp.ll
Removed:
################################################################################
diff --git a/clang/test/CodeGenObjC/exceptions.m b/clang/test/CodeGenObjC/exceptions.m
index 741f8a819158..3bb4f86cf025 100644
--- a/clang/test/CodeGenObjC/exceptions.m
+++ b/clang/test/CodeGenObjC/exceptions.m
@@ -97,7 +97,7 @@ void f3() {
// CHECK: call void @objc_exception_try_exit(
f3_helper(0, &x);
} @finally {
- // CHECK: [[DEST1:%.*]] = phi i32 [ 0, {{%.*}} ], [ 3, {{%.*}} ]
+ // CHECK: [[DEST1:%.*]] = phi i1 [ true, {{%.*}} ], [ false, {{%.*}} ]
// CHECK: call void @objc_exception_try_enter
// CHECK: call i32 @_setjmp
@try {
@@ -105,7 +105,7 @@ void f3() {
// CHECK: call void @objc_exception_try_exit(
f3_helper(1, &x);
} @finally {
- // CHECK: [[DEST2:%.*]] = phi i32 [ 0, {{%.*}} ], [ 5, {{%.*}} ]
+ // CHECK: [[DEST2:%.*]] = phi i1 [ true, {{%.*}} ], [ false, {{%.*}} ]
// CHECK: call void @f3_helper(i32 2, i32* nonnull [[X]])
f3_helper(2, &x);
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 48375a1a323f..a7b9ecb9bf3b 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1452,6 +1452,27 @@ Instruction *InstCombiner::foldICmpWithConstant(ICmpInst &Cmp) {
if (Instruction *Res = processUGT_ADDCST_ADD(Cmp, A, B, CI2, CI, *this))
return Res;
+ // icmp(phi(C1, C2, ...), C) -> phi(icmp(C1, C), icmp(C2, C), ...).
+ Constant *C = dyn_cast<Constant>(Op1);
+ if (!C)
+ return nullptr;
+
+ if (auto *Phi = dyn_cast<PHINode>(Op0))
+ if (all_of(Phi->operands(), [](Value *V) { return isa<Constant>(V); })) {
+ Type *Ty = Cmp.getType();
+ Builder.SetInsertPoint(Phi);
+ PHINode *NewPhi =
+ Builder.CreatePHI(Ty, Phi->getNumOperands());
+ for (BasicBlock *Predecessor : predecessors(Phi->getParent())) {
+ auto *Input =
+ cast<Constant>(Phi->getIncomingValueForBlock(Predecessor));
+ auto *BoolInput = ConstantExpr::getCompare(Pred, Input, C);
+ NewPhi->addIncoming(BoolInput, Predecessor);
+ }
+ NewPhi->takeName(&Cmp);
+ return replaceInstUsesWith(Cmp, NewPhi);
+ }
+
return nullptr;
}
diff --git a/llvm/test/Transforms/InstCombine/icmp-constant-phi.ll b/llvm/test/Transforms/InstCombine/icmp-constant-phi.ll
index 9753149f8012..7d4b9294143f 100644
--- a/llvm/test/Transforms/InstCombine/icmp-constant-phi.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-constant-phi.ll
@@ -2,8 +2,6 @@
; RUN: opt < %s -instcombine -S | FileCheck %s
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
-; TODO: Replace with boolean Phi.
-
define i1 @test_eq(i1 %cond) {
; CHECK-LABEL: @test_eq(
; CHECK-NEXT: entry:
@@ -13,10 +11,9 @@ define i1 @test_eq(i1 %cond) {
; CHECK: if.false:
; CHECK-NEXT: br label [[MERGE]]
; CHECK: merge:
-; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 123, [[IF_TRUE]] ], [ 456, [[IF_FALSE]] ]
+; CHECK-NEXT: [[COMPARE:%.*]] = phi i1 [ true, [[IF_FALSE]] ], [ false, [[IF_TRUE]] ]
; CHECK-NEXT: br label [[EXIT:%.*]]
; CHECK: exit:
-; CHECK-NEXT: [[COMPARE:%.*]] = icmp eq i32 [[PHI]], 456
; CHECK-NEXT: ret i1 [[COMPARE]]
;
entry:
@@ -46,10 +43,9 @@ define i1 @test_slt(i1 %cond) {
; CHECK: if.false:
; CHECK-NEXT: br label [[MERGE]]
; CHECK: merge:
-; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 123, [[IF_TRUE]] ], [ 456, [[IF_FALSE]] ]
+; CHECK-NEXT: [[COMPARE:%.*]] = phi i1 [ false, [[IF_FALSE]] ], [ true, [[IF_TRUE]] ]
; CHECK-NEXT: br label [[EXIT:%.*]]
; CHECK: exit:
-; CHECK-NEXT: [[COMPARE:%.*]] = icmp ult i32 [[PHI]], 456
; CHECK-NEXT: ret i1 [[COMPARE]]
;
entry:
@@ -110,10 +106,9 @@ define i1 @test_ne(i1 %cond) {
; CHECK: if.false:
; CHECK-NEXT: br label [[MERGE]]
; CHECK: merge:
-; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 123, [[IF_TRUE]] ], [ 456, [[IF_FALSE]] ]
+; CHECK-NEXT: [[COMPARE:%.*]] = phi i1 [ false, [[IF_FALSE]] ], [ true, [[IF_TRUE]] ]
; CHECK-NEXT: br label [[EXIT:%.*]]
; CHECK: exit:
-; CHECK-NEXT: [[COMPARE:%.*]] = icmp ne i32 [[PHI]], 456
; CHECK-NEXT: ret i1 [[COMPARE]]
;
entry:
@@ -133,3 +128,164 @@ exit:
%compare = icmp ne i32 %phi, 456
ret i1 %compare
}
+
+define i1 @test_ne_undef(i1 %cond) {
+; CHECK-LABEL: @test_ne_undef(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK: if.true:
+; CHECK-NEXT: br label [[MERGE:%.*]]
+; CHECK: if.false:
+; CHECK-NEXT: br label [[MERGE]]
+; CHECK: merge:
+; CHECK-NEXT: br label [[EXIT:%.*]]
+; CHECK: exit:
+; CHECK-NEXT: ret i1 false
+;
+entry:
+ br i1 %cond, label %if.true, label %if.false
+
+if.true:
+ br label %merge
+
+if.false:
+ br label %merge
+
+merge:
+ %phi = phi i32 [undef, %if.true], [456, %if.false]
+ br label %exit
+
+exit:
+ %compare = icmp ne i32 %phi, 456
+ ret i1 %compare
+}
+
+define <2 x i1> @test_ne_int_vector(i1 %cond) {
+; CHECK-LABEL: @test_ne_int_vector(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK: if.true:
+; CHECK-NEXT: br label [[MERGE:%.*]]
+; CHECK: if.false:
+; CHECK-NEXT: br label [[MERGE]]
+; CHECK: merge:
+; CHECK-NEXT: [[COMPARE:%.*]] = phi <2 x i1> [ <i1 true, i1 false>, [[IF_FALSE]] ], [ <i1 false, i1 true>, [[IF_TRUE]] ]
+; CHECK-NEXT: br label [[EXIT:%.*]]
+; CHECK: exit:
+; CHECK-NEXT: ret <2 x i1> [[COMPARE]]
+;
+entry:
+ br i1 %cond, label %if.true, label %if.false
+
+if.true:
+ br label %merge
+
+if.false:
+ br label %merge
+
+merge:
+ %phi = phi <2 x i32> [<i32 123, i32 123>, %if.true], [<i32 456, i32 456>, %if.false]
+ br label %exit
+
+exit:
+ %compare = icmp ne <2 x i32> %phi, <i32 123, i32 456>
+ ret <2 x i1> %compare
+}
+
+; TODO: We can also constant-fold this comparison for floats.
+define i1 @test_ne_float(i1 %cond) {
+; CHECK-LABEL: @test_ne_float(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK: if.true:
+; CHECK-NEXT: br label [[MERGE:%.*]]
+; 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]]
+;
+entry:
+ br i1 %cond, label %if.true, label %if.false
+
+if.true:
+ br label %merge
+
+if.false:
+ br label %merge
+
+merge:
+ %phi = phi float [1.0, %if.true], [1.25, %if.false]
+ br label %exit
+
+exit:
+ %compare = fcmp one float %phi, 1.25
+ ret i1 %compare
+}
+
+define i1 @test_ne_float_undef(i1 %cond) {
+; CHECK-LABEL: @test_ne_float_undef(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK: if.true:
+; CHECK-NEXT: br label [[MERGE:%.*]]
+; CHECK: if.false:
+; CHECK-NEXT: br label [[MERGE]]
+; CHECK: merge:
+; CHECK-NEXT: br label [[EXIT:%.*]]
+; CHECK: exit:
+; CHECK-NEXT: ret i1 true
+;
+entry:
+ br i1 %cond, label %if.true, label %if.false
+
+if.true:
+ br label %merge
+
+if.false:
+ br label %merge
+
+merge:
+ %phi = phi float [1.0, %if.true], [undef, %if.false]
+ br label %exit
+
+exit:
+ %compare = fcmp one float %phi, 1.25
+ ret i1 %compare
+}
+
+define <2 x i1> @test_ne_float_vector(i1 %cond) {
+; CHECK-LABEL: @test_ne_float_vector(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK: if.true:
+; CHECK-NEXT: br label [[MERGE:%.*]]
+; 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: 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]]
+;
+entry:
+ br i1 %cond, label %if.true, label %if.false
+
+if.true:
+ br label %merge
+
+if.false:
+ br label %merge
+
+merge:
+ %phi = phi <2 x float> [<float 123.25, float 123.25>, %if.true], [<float 456.25, float 456.25>, %if.false]
+ br label %exit
+
+exit:
+ %compare = fcmp one <2 x float> %phi, <float 123.25, float 456.25>
+ ret <2 x i1> %compare
+}
diff --git a/llvm/test/Transforms/InstCombine/indexed-gep-compares.ll b/llvm/test/Transforms/InstCombine/indexed-gep-compares.ll
index 71afed438d10..859fd6437bb3 100644
--- a/llvm/test/Transforms/InstCombine/indexed-gep-compares.ll
+++ b/llvm/test/Transforms/InstCombine/indexed-gep-compares.ll
@@ -182,8 +182,7 @@ bb10:
ret i1 %cmp
}
; CHECK-LABEL: @test7(
-; CHECK: %[[phi:.*]] = phi i64* [ @pr30402, %entry ], [ getelementptr inbounds (i64, i64* @pr30402, i32 1), %bb7 ]
-; CHECK: %[[cmp:.*]] = icmp eq i64* %[[phi]], getelementptr inbounds (i64, i64* @pr30402, i32 1)
+; CHECK: %[[cmp:.*]] = phi i1 [ true, %bb7 ], [ false, %entry ]
; CHECK: ret i1 %[[cmp]]
diff --git a/llvm/test/Transforms/InstCombine/zext-or-icmp.ll b/llvm/test/Transforms/InstCombine/zext-or-icmp.ll
index 6c65032cebe9..973c5a53abac 100644
--- a/llvm/test/Transforms/InstCombine/zext-or-icmp.ll
+++ b/llvm/test/Transforms/InstCombine/zext-or-icmp.ll
@@ -40,8 +40,8 @@ block2:
ret i32 %conv2
; CHECK-LABEL: dont_widen_undef(
-; CHECK: %m.011 = phi i32 [ 33, %entry ], [ 0, %block1 ]
-; CHECK-NEXT: %cmp.i = icmp ugt i32 %m.011, 1
+; CHECK: %cmp.i = phi i1 [ false, %block1 ], [ true, %entry ]
+; CHECK-NEXT: %m.011 = phi i32 [ 0, %block1 ], [ 33, %entry ]
; CHECK-NEXT: %m.1.op = lshr i32 1, %m.011
; CHECK-NEXT: %sext.mask = and i32 %m.1.op, 65535
; CHECK-NEXT: %cmp115 = icmp ne i32 %sext.mask, 0
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