[llvm] de59d22 - [InstCombine] Support logical ops in foldAndOrOfICmpEqZeroAndICmp()
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Tue Dec 13 01:37:08 PST 2022
Author: Nikita Popov
Date: 2022-12-13T10:36:55+01:00
New Revision: de59d222abb2c8d65f6225b314fa6486b1b66809
URL: https://github.com/llvm/llvm-project/commit/de59d222abb2c8d65f6225b314fa6486b1b66809
DIFF: https://github.com/llvm/llvm-project/commit/de59d222abb2c8d65f6225b314fa6486b1b66809.diff
LOG: [InstCombine] Support logical ops in foldAndOrOfICmpEqZeroAndICmp()
If the and/or is logical and one of the operands only occurs on the
RHS, we need to freeze it: https://alive2.llvm.org/ce/z/vuMuE_
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
llvm/test/Transforms/InstCombine/icmp.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 9538f0f4a6bf..8a8185b2cb4c 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2584,8 +2584,9 @@ Value *InstCombinerImpl::matchSelectFromAndOr(Value *A, Value *C, Value *B,
// (icmp eq X, 0) | (icmp ult Other, X) -> (icmp ule Other, X-1)
// (icmp ne X, 0) & (icmp uge Other, X) -> (icmp ugt Other, X-1)
-Value *foldAndOrOfICmpEqZeroAndICmp(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
- IRBuilderBase &Builder) {
+static Value *foldAndOrOfICmpEqZeroAndICmp(ICmpInst *LHS, ICmpInst *RHS,
+ bool IsAnd, bool IsLogical,
+ IRBuilderBase &Builder) {
ICmpInst::Predicate LPred =
IsAnd ? LHS->getInversePredicate() : LHS->getPredicate();
ICmpInst::Predicate RPred =
@@ -2604,6 +2605,8 @@ Value *foldAndOrOfICmpEqZeroAndICmp(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
else
return nullptr;
+ if (IsLogical)
+ Other = Builder.CreateFreeze(Other);
return Builder.CreateICmp(
IsAnd ? ICmpInst::ICMP_ULT : ICmpInst::ICMP_UGE,
Builder.CreateAdd(LHS0, Constant::getAllOnesValue(LHS0->getType())),
@@ -2652,14 +2655,14 @@ Value *InstCombinerImpl::foldAndOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, IsAnd, IsLogical, Builder))
return V;
- // TODO: One of these directions is fine with logical and/or, the other could
- // be supported by inserting freeze.
- if (!IsLogical) {
- if (Value *V = foldAndOrOfICmpEqZeroAndICmp(LHS, RHS, IsAnd, Builder))
- return V;
- if (Value *V = foldAndOrOfICmpEqZeroAndICmp(RHS, LHS, IsAnd, Builder))
- return V;
- }
+ if (Value *V =
+ foldAndOrOfICmpEqZeroAndICmp(LHS, RHS, IsAnd, IsLogical, Builder))
+ return V;
+ // We can treat logical like bitwise here, because both operands are used on
+ // the LHS, and as such poison from both will propagate.
+ if (Value *V = foldAndOrOfICmpEqZeroAndICmp(RHS, LHS, IsAnd,
+ /*IsLogical*/ false, Builder))
+ return V;
// TODO: Verify whether this is safe for logical and/or.
if (!IsLogical) {
diff --git a/llvm/test/Transforms/InstCombine/icmp.ll b/llvm/test/Transforms/InstCombine/icmp.ll
index 18d47bca9f0d..0041323c7ccd 100644
--- a/llvm/test/Transforms/InstCombine/icmp.ll
+++ b/llvm/test/Transforms/InstCombine/icmp.ll
@@ -2172,9 +2172,9 @@ define i1 @or_icmp_eq_B_0_icmp_ult_A_B(i64 %a, i64 %b) {
define i1 @or_icmp_eq_B_0_icmp_ult_A_B_logical(i64 %a, i64 %b) {
; CHECK-LABEL: @or_icmp_eq_B_0_icmp_ult_A_B_logical(
-; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[B:%.*]], 0
-; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i64 [[A:%.*]], [[B]]
-; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP1]], i1 true, i1 [[TMP2]]
+; CHECK-NEXT: [[TMP1:%.*]] = freeze i64 [[A:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = add i64 [[B:%.*]], -1
+; CHECK-NEXT: [[TMP3:%.*]] = icmp uge i64 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[TMP3]]
;
%1 = icmp eq i64 %b, 0
@@ -2306,9 +2306,9 @@ define i1 @and_icmp_ne_B_0_icmp_uge_A_B_commuted1_logical(i64 %a, i64 %b) {
define i1 @and_icmp_ne_B_0_icmp_uge_A_B_commuted2_logical(i64 %a, i64 %b) {
; CHECK-LABEL: @and_icmp_ne_B_0_icmp_uge_A_B_commuted2_logical(
-; CHECK-NEXT: [[TMP1:%.*]] = icmp ne i64 [[B:%.*]], 0
-; CHECK-NEXT: [[TMP2:%.*]] = icmp ule i64 [[B]], [[A:%.*]]
-; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP1]], i1 [[TMP2]], i1 false
+; CHECK-NEXT: [[TMP1:%.*]] = freeze i64 [[A:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = add i64 [[B:%.*]], -1
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ult i64 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[TMP3]]
;
%1 = icmp ne i64 %b, 0
@@ -2418,9 +2418,9 @@ define i1 @and_icmp_ne_B_0_icmp_uge_A_B_wrong_op2(i64 %a, i64 %b, i64 %c) {
define i1 @and_icmp_ne_B_0_icmp_uge_A_B_logical(i64 %a, i64 %b) {
; CHECK-LABEL: @and_icmp_ne_B_0_icmp_uge_A_B_logical(
-; CHECK-NEXT: [[TMP1:%.*]] = icmp ne i64 [[B:%.*]], 0
-; CHECK-NEXT: [[TMP2:%.*]] = icmp uge i64 [[A:%.*]], [[B]]
-; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP1]], i1 [[TMP2]], i1 false
+; CHECK-NEXT: [[TMP1:%.*]] = freeze i64 [[A:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = add i64 [[B:%.*]], -1
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ult i64 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[TMP3]]
;
%1 = icmp ne i64 %b, 0
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