[llvm] [ConstraintElim] Check if second op implies first for And. (PR #75750)
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Sun Dec 17 13:11:09 PST 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
Author: Florian Hahn (fhahn)
<details>
<summary>Changes</summary>
Generalize checkAndSecondOpImpliedByFirst to also check if the second operand implies the first.
---
Full diff: https://github.com/llvm/llvm-project/pull/75750.diff
5 Files Affected:
- (modified) llvm/lib/Transforms/Scalar/ConstraintElimination.cpp (+24-15)
- (modified) llvm/test/Transforms/ConstraintElimination/and-implied-by-operands.ll (+4-4)
- (modified) llvm/test/Transforms/ConstraintElimination/and.ll (+2-2)
- (modified) llvm/test/Transforms/ConstraintElimination/gep-arithmetic-signed-predicates.ll (+1-1)
- (modified) llvm/test/Transforms/ConstraintElimination/geps-precondition-overflow-check.ll (+3-3)
``````````diff
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index 18266ba0789897..da019ecbc7c429 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -1365,16 +1365,24 @@ removeEntryFromStack(const StackEntry &E, ConstraintInfo &Info,
ReproducerCondStack.pop_back();
}
-/// Check if the first condition for an AND implies the second.
-static bool checkAndSecondOpImpliedByFirst(
- FactOrCheck &CB, ConstraintInfo &Info, Module *ReproducerModule,
- SmallVectorImpl<ReproducerEntry> &ReproducerCondStack,
- SmallVectorImpl<StackEntry> &DFSInStack) {
+/// Check if either the first condition of an AND is implied by the second or
+/// vice versa.
+static bool
+checkAndOpImpliedByOther(FactOrCheck &CB, ConstraintInfo &Info,
+ Module *ReproducerModule,
+ SmallVectorImpl<ReproducerEntry> &ReproducerCondStack,
+ SmallVectorImpl<StackEntry> &DFSInStack) {
CmpInst::Predicate Pred;
Value *A, *B;
Instruction *And = CB.getContextInst();
- if (!match(And->getOperand(0), m_ICmp(Pred, m_Value(A), m_Value(B))))
+ CmpInst *CmpToCheck = cast<CmpInst>(CB.getInstructionToSimplify());
+ unsigned OtherOpIdx = And->getOperand(0) == CmpToCheck ? 1 : 0;
+
+ if (OtherOpIdx != 0 && isa<SelectInst>(And))
+ return false;
+
+ if (!match(And->getOperand(OtherOpIdx), m_ICmp(Pred, m_Value(A), m_Value(B))))
return false;
// Optimistically add fact from first condition.
@@ -1385,11 +1393,12 @@ static bool checkAndSecondOpImpliedByFirst(
bool Changed = false;
// Check if the second condition can be simplified now.
- ICmpInst *Cmp = cast<ICmpInst>(And->getOperand(1));
- if (auto ImpliedCondition = checkCondition(
- Cmp->getPredicate(), Cmp->getOperand(0), Cmp->getOperand(1), Cmp,
- Info, CB.NumIn, CB.NumOut, CB.getContextInst())) {
- And->setOperand(1, ConstantInt::getBool(And->getType(), *ImpliedCondition));
+ if (auto ImpliedCondition =
+ checkCondition(CmpToCheck->getPredicate(), CmpToCheck->getOperand(0),
+ CmpToCheck->getOperand(1), CmpToCheck, Info, CB.NumIn,
+ CB.NumOut, CB.getContextInst())) {
+ And->setOperand(1 - OtherOpIdx,
+ ConstantInt::getBool(And->getType(), *ImpliedCondition));
Changed = true;
}
@@ -1609,11 +1618,11 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT, LoopInfo &LI,
bool Simplified = checkAndReplaceCondition(
Cmp, Info, CB.NumIn, CB.NumOut, CB.getContextInst(),
ReproducerModule.get(), ReproducerCondStack, S.DT, ToRemove);
- if (!Simplified && match(CB.getContextInst(),
- m_LogicalAnd(m_Value(), m_Specific(Inst)))) {
+ if (!Simplified &&
+ match(CB.getContextInst(), m_LogicalAnd(m_Value(), m_Value()))) {
Simplified =
- checkAndSecondOpImpliedByFirst(CB, Info, ReproducerModule.get(),
- ReproducerCondStack, DFSInStack);
+ checkAndOpImpliedByByOther(CB, Info, ReproducerModule.get(),
+ ReproducerCondStack, DFSInStack);
}
Changed |= Simplified;
}
diff --git a/llvm/test/Transforms/ConstraintElimination/and-implied-by-operands.ll b/llvm/test/Transforms/ConstraintElimination/and-implied-by-operands.ll
index dc3b0f17c79602..3d2a480195abc3 100644
--- a/llvm/test/Transforms/ConstraintElimination/and-implied-by-operands.ll
+++ b/llvm/test/Transforms/ConstraintElimination/and-implied-by-operands.ll
@@ -31,7 +31,7 @@ define i1 @test_first_and_condition_implied_by_second_ops(i8 %x) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[C_1:%.*]] = icmp ugt i8 [[X:%.*]], 10
; CHECK-NEXT: [[T_1:%.*]] = icmp ugt i8 [[X]], 5
-; CHECK-NEXT: [[AND:%.*]] = and i1 [[T_1]], [[C_1]]
+; CHECK-NEXT: [[AND:%.*]] = and i1 true, [[C_1]]
; CHECK-NEXT: br i1 [[AND]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: ret i1 false
@@ -105,7 +105,7 @@ define i1 @test_same_cond_for_and(i8 %x) {
; CHECK-LABEL: @test_same_cond_for_and(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[C_1:%.*]] = icmp ugt i8 [[X:%.*]], 10
-; CHECK-NEXT: [[AND:%.*]] = and i1 [[C_1]], true
+; CHECK-NEXT: [[AND:%.*]] = and i1 true, [[C_1]]
; CHECK-NEXT: br i1 [[AND]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: ret i1 false
@@ -128,7 +128,7 @@ define i1 @test_same_cond_for_and_select_form(i8 %x) {
; CHECK-LABEL: @test_same_cond_for_and_select_form(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[C_1:%.*]] = icmp ugt i8 [[X:%.*]], 10
-; CHECK-NEXT: [[AND:%.*]] = select i1 [[C_1]], i1 true, i1 false
+; CHECK-NEXT: [[AND:%.*]] = select i1 [[C_1]], i1 [[C_1]], i1 false
; CHECK-NEXT: br i1 [[AND]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: ret i1 false
@@ -152,7 +152,7 @@ define i1 @test_second_and_condition_not_implied_by_first(i8 %x) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[C_1:%.*]] = icmp ugt i8 [[X:%.*]], 10
; CHECK-NEXT: [[C_2:%.*]] = icmp ugt i8 [[X]], 5
-; CHECK-NEXT: [[AND:%.*]] = and i1 [[C_2]], [[C_1]]
+; CHECK-NEXT: [[AND:%.*]] = and i1 true, [[C_1]]
; CHECK-NEXT: br i1 [[AND]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: ret i1 false
diff --git a/llvm/test/Transforms/ConstraintElimination/and.ll b/llvm/test/Transforms/ConstraintElimination/and.ll
index 389a676651a428..f9824df3975e97 100644
--- a/llvm/test/Transforms/ConstraintElimination/and.ll
+++ b/llvm/test/Transforms/ConstraintElimination/and.ll
@@ -438,7 +438,7 @@ define i1 @test_and_chain_select_ule(i4 %x, i4 %y, i4 %z, i4 %a) {
; CHECK-NEXT: [[C_2:%.*]] = icmp ule i4 [[Y]], [[Z:%.*]]
; CHECK-NEXT: [[C_3:%.*]] = icmp ule i4 3, [[X]]
; CHECK-NEXT: [[C_4:%.*]] = icmp ule i4 3, [[A:%.*]]
-; CHECK-NEXT: [[AND_1:%.*]] = select i1 [[C_1]], i1 true, i1 false
+; CHECK-NEXT: [[AND_1:%.*]] = select i1 [[C_1]], i1 [[C_1]], i1 false
; CHECK-NEXT: [[AND_2:%.*]] = select i1 [[AND_1]], i1 [[C_3]], i1 false
; CHECK-NEXT: [[AND_3:%.*]] = select i1 [[C_4]], i1 [[AND_2]], i1 false
; CHECK-NEXT: br i1 [[AND_3]], label [[BB1:%.*]], label [[EXIT:%.*]]
@@ -522,7 +522,7 @@ define i1 @test_and_chain_select_ule_logical_or(i4 %x, i4 %y, i4 %z, i4 %a) {
; CHECK-NEXT: [[C_2:%.*]] = icmp ule i4 [[Y]], [[Z:%.*]]
; CHECK-NEXT: [[C_3:%.*]] = icmp ule i4 3, [[X]]
; CHECK-NEXT: [[C_4:%.*]] = icmp ule i4 3, [[A:%.*]]
-; CHECK-NEXT: [[AND_1:%.*]] = select i1 [[C_1]], i1 true, i1 false
+; CHECK-NEXT: [[AND_1:%.*]] = select i1 [[C_1]], i1 [[C_1]], i1 false
; CHECK-NEXT: [[AND_2:%.*]] = select i1 [[AND_1]], i1 [[C_3]], i1 false
; CHECK-NEXT: [[AND_3:%.*]] = select i1 [[C_4]], i1 [[AND_2]], i1 false
; CHECK-NEXT: [[AND_4:%.*]] = select i1 [[AND_3]], i1 true, i1 false
diff --git a/llvm/test/Transforms/ConstraintElimination/gep-arithmetic-signed-predicates.ll b/llvm/test/Transforms/ConstraintElimination/gep-arithmetic-signed-predicates.ll
index d8ed479f3ee671..96ff98b00538ef 100644
--- a/llvm/test/Transforms/ConstraintElimination/gep-arithmetic-signed-predicates.ll
+++ b/llvm/test/Transforms/ConstraintElimination/gep-arithmetic-signed-predicates.ll
@@ -611,7 +611,7 @@ define i4 @ptr_N_signed_positive_assume(ptr %src, ptr %lower, ptr %upper, i16 %N
; CHECK: step.check:
; CHECK-NEXT: [[STEP_POS:%.*]] = icmp sge i16 [[STEP:%.*]], 0
; CHECK-NEXT: [[STEP_SLT_N:%.*]] = icmp slt i16 [[STEP]], [[N]]
-; CHECK-NEXT: [[AND_STEP:%.*]] = and i1 [[STEP_POS]], false
+; CHECK-NEXT: [[AND_STEP:%.*]] = and i1 false, [[STEP_SLT_N]]
; CHECK-NEXT: br i1 [[AND_STEP]], label [[PTR_CHECK:%.*]], label [[EXIT:%.*]]
; CHECK: ptr.check:
; CHECK-NEXT: [[SRC_STEP:%.*]] = getelementptr inbounds i8, ptr [[SRC]], i16 [[STEP]]
diff --git a/llvm/test/Transforms/ConstraintElimination/geps-precondition-overflow-check.ll b/llvm/test/Transforms/ConstraintElimination/geps-precondition-overflow-check.ll
index 47923836187845..834db0418b4d46 100644
--- a/llvm/test/Transforms/ConstraintElimination/geps-precondition-overflow-check.ll
+++ b/llvm/test/Transforms/ConstraintElimination/geps-precondition-overflow-check.ll
@@ -36,7 +36,7 @@ define i1 @overflow_check_2_and(ptr %dst) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[DST_5:%.*]] = getelementptr i32, ptr [[DST:%.*]], i64 5
; CHECK-NEXT: [[DST_5_UGE:%.*]] = icmp uge ptr [[DST_5]], [[DST]]
-; CHECK-NEXT: [[AND:%.*]] = and i1 [[DST_5_UGE]], true
+; CHECK-NEXT: [[AND:%.*]] = and i1 true, [[DST_5_UGE]]
; CHECK-NEXT: br i1 [[AND]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: [[DST_4:%.*]] = getelementptr i32, ptr [[DST]], i64 4
@@ -65,7 +65,7 @@ define i1 @overflow_check_3_and(ptr %dst) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[DST_5:%.*]] = getelementptr i32, ptr [[DST:%.*]], i64 5
; CHECK-NEXT: [[DST_5_UGE:%.*]] = icmp uge ptr [[DST_5]], [[DST]]
-; CHECK-NEXT: [[AND:%.*]] = and i1 [[DST_5_UGE]], true
+; CHECK-NEXT: [[AND:%.*]] = and i1 true, [[DST_5_UGE]]
; CHECK-NEXT: br i1 [[AND]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: [[DST_4:%.*]] = getelementptr i32, ptr [[DST]], i64 4
@@ -98,7 +98,7 @@ define i1 @overflow_check_4_and(ptr %dst) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[DST_5:%.*]] = getelementptr i32, ptr [[DST:%.*]], i64 5
; CHECK-NEXT: [[DST_5_UGE:%.*]] = icmp uge ptr [[DST_5]], [[DST]]
-; CHECK-NEXT: [[AND:%.*]] = and i1 [[DST_5_UGE]], true
+; CHECK-NEXT: [[AND:%.*]] = and i1 true, [[DST_5_UGE]]
; CHECK-NEXT: br i1 [[AND]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: [[DST_4:%.*]] = getelementptr i32, ptr [[DST]], i64 4
``````````
</details>
https://github.com/llvm/llvm-project/pull/75750
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