[llvm] 1d23d60 - [ConstraintElimination] Add function arguments to constraint system before solving
Zain Jaffal via llvm-commits
llvm-commits at lists.llvm.org
Mon Apr 3 06:17:17 PDT 2023
Author: Zain Jaffal
Date: 2023-04-03T14:16:49+01:00
New Revision: 1d23d60c8d0406b9163d223d2721c5e4f1932f50
URL: https://github.com/llvm/llvm-project/commit/1d23d60c8d0406b9163d223d2721c5e4f1932f50
DIFF: https://github.com/llvm/llvm-project/commit/1d23d60c8d0406b9163d223d2721c5e4f1932f50.diff
LOG: [ConstraintElimination] Add function arguments to constraint system before solving
If there is an optimisation opportunity and the function argument hasn’t been added to constraint
system through previous facts we fail to optimise it.
It might be a good idea to start the constraint system with all the function arguments added to the system
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D144879
Added:
Modified:
llvm/include/llvm/Analysis/ConstraintSystem.h
llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
llvm/test/Transforms/ConstraintElimination/transfer-signed-facts-to-unsigned.ll
Removed:
################################################################################
diff --git a/llvm/include/llvm/Analysis/ConstraintSystem.h b/llvm/include/llvm/Analysis/ConstraintSystem.h
index 05785d19f0335..29ba99b0f6d97 100644
--- a/llvm/include/llvm/Analysis/ConstraintSystem.h
+++ b/llvm/include/llvm/Analysis/ConstraintSystem.h
@@ -19,7 +19,6 @@
namespace llvm {
class Value;
-
class ConstraintSystem {
struct Entry {
int64_t Coefficient;
@@ -68,8 +67,14 @@ class ConstraintSystem {
public:
ConstraintSystem() {}
+ ConstraintSystem(ArrayRef<Value *> FunctionArgs) {
+ NumVariables += FunctionArgs.size();
+ for (auto *Arg : FunctionArgs) {
+ Value2Index.insert({Arg, Value2Index.size() + 1});
+ }
+ }
ConstraintSystem(const DenseMap<Value *, unsigned> &Value2Index)
- : Value2Index(Value2Index) {}
+ : NumVariables(Value2Index.size()), Value2Index(Value2Index) {}
bool addVariableRow(ArrayRef<int64_t> R) {
assert(Constraints.empty() || R.size() == NumVariables);
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index d0b59d6329fc4..762061b1435de 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -139,7 +139,8 @@ class ConstraintInfo {
const DataLayout &DL;
public:
- ConstraintInfo(const DataLayout &DL) : DL(DL) {}
+ ConstraintInfo(const DataLayout &DL, ArrayRef<Value *> FunctionArgs)
+ : UnsignedCS(FunctionArgs), SignedCS(FunctionArgs), DL(DL) {}
DenseMap<Value *, unsigned> &getValue2Index(bool Signed) {
return Signed ? SignedCS.getValue2Index() : UnsignedCS.getValue2Index();
@@ -1087,8 +1088,10 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT,
OptimizationRemarkEmitter &ORE) {
bool Changed = false;
DT.updateDFSNumbers();
-
- ConstraintInfo Info(F.getParent()->getDataLayout());
+ SmallVector<Value *> FunctionArgs;
+ for (Value &Arg : F.args())
+ FunctionArgs.push_back(&Arg);
+ ConstraintInfo Info(F.getParent()->getDataLayout(), FunctionArgs);
State S(DT);
std::unique_ptr<Module> ReproducerModule(
DumpReproducers ? new Module(F.getName(), F.getContext()) : nullptr);
diff --git a/llvm/test/Transforms/ConstraintElimination/transfer-signed-facts-to-unsigned.ll b/llvm/test/Transforms/ConstraintElimination/transfer-signed-facts-to-unsigned.ll
index 2baa6b001d86e..cc22ea752eeba 100644
--- a/llvm/test/Transforms/ConstraintElimination/transfer-signed-facts-to-unsigned.ll
+++ b/llvm/test/Transforms/ConstraintElimination/transfer-signed-facts-to-unsigned.ll
@@ -295,8 +295,6 @@ else:
ret i1 1
}
-; TODO: Even though %cnt is not known signed positive %cmp can be simplified
-; because %add.ptr uses it zero-extended.
define i1 @cnt_not_known_positive_sgt_against_base_with_zext(ptr %p, i32 %cnt) {
; CHECK-LABEL: @cnt_not_known_positive_sgt_against_base_with_zext(
; CHECK-NEXT: entry:
@@ -305,7 +303,7 @@ define i1 @cnt_not_known_positive_sgt_against_base_with_zext(ptr %p, i32 %cnt) {
; CHECK-NEXT: [[EXT:%.*]] = zext i32 [[CNT]] to i64
; CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 [[EXT]]
; CHECK-NEXT: [[CMP_1:%.*]] = icmp uge ptr [[ADD_PTR]], [[P]]
-; CHECK-NEXT: br i1 [[CMP_1]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK-NEXT: br i1 true, label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: ret i1 false
; CHECK: else:
@@ -326,8 +324,6 @@ else:
ret i1 1
}
-; TODO: Even though %cnt is not known signed positive %cmp can be simplified
-; because %add.ptr uses it zero-extended.
define i1 @cnt_not_known_positive_sge_against_base_with_zext(ptr %p, i32 %cnt) {
; CHECK-LABEL: @cnt_not_known_positive_sge_against_base_with_zext(
; CHECK-NEXT: entry:
@@ -336,7 +332,7 @@ define i1 @cnt_not_known_positive_sge_against_base_with_zext(ptr %p, i32 %cnt) {
; CHECK-NEXT: [[EXT:%.*]] = zext i32 [[CNT]] to i64
; CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 [[EXT]]
; CHECK-NEXT: [[CMP_1:%.*]] = icmp uge ptr [[ADD_PTR]], [[P]]
-; CHECK-NEXT: br i1 [[CMP_1]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK-NEXT: br i1 true, label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: ret i1 false
; CHECK: else:
@@ -453,7 +449,6 @@ else:
ret i1 1
}
-; TODO: Even though %cnt is not known signed positive %cmp can be simplified
; because %add.ptr uses it zero-extended.
define i1 @cnt_not_known_positive_from_branch_check_against_base_struct_ugt_with_zext(ptr %p, i32 %cnt) {
; CHECK-LABEL: @cnt_not_known_positive_from_branch_check_against_base_struct_ugt_with_zext(
@@ -464,7 +459,7 @@ define i1 @cnt_not_known_positive_from_branch_check_against_base_struct_ugt_with
; CHECK-NEXT: [[EXT:%.*]] = zext i32 [[CNT]] to i64
; CHECK-NEXT: [[GEP_EXT:%.*]] = getelementptr inbounds [[T:%.*]], ptr [[P:%.*]], i64 0, i32 1, i64 [[EXT]]
; CHECK-NEXT: [[CMP_1:%.*]] = icmp ugt ptr [[GEP_EXT]], [[P]]
-; CHECK-NEXT: br i1 [[CMP_1]], label [[THEN:%.*]], label [[ELSE]]
+; CHECK-NEXT: br i1 true, label [[THEN:%.*]], label [[ELSE]]
; CHECK: then:
; CHECK-NEXT: ret i1 false
; CHECK: else:
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