[CVP] Handle use-site conditions in domain-based folds

As a side-effect, this switchem them to use getConstantRange() rather than getPredicateAt(). getPredicateAt() is not supposed to be more powerful than getConstantRange() for non-equality comparisons (as long as block values are used).
llvm · Jan 17, 2023 · a444fe0 · a444fe0
1 parent 12cb1cb
commit a444fe0
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Showing 2 changed files with 23 additions and 35 deletions.
diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -692,26 +692,13 @@ static bool processCallSite(CallBase &CB, LazyValueInfo *LVI) {
   return true;
 }
 
-static bool isNonNegative(Value *V, LazyValueInfo *LVI, Instruction *CxtI) {
-  Constant *Zero = ConstantInt::get(V->getType(), 0);
-  auto Result = LVI->getPredicateAt(ICmpInst::ICMP_SGE, V, Zero, CxtI,
-                                    /*UseBlockValue=*/true);
-  return Result == LazyValueInfo::True;
-}
-
-static bool isNonPositive(Value *V, LazyValueInfo *LVI, Instruction *CxtI) {
-  Constant *Zero = ConstantInt::get(V->getType(), 0);
-  auto Result = LVI->getPredicateAt(ICmpInst::ICMP_SLE, V, Zero, CxtI,
-                                    /*UseBlockValue=*/true);
-  return Result == LazyValueInfo::True;
-}
-
 enum class Domain { NonNegative, NonPositive, Unknown };
 
-Domain getDomain(Value *V, LazyValueInfo *LVI, Instruction *CxtI) {
-  if (isNonNegative(V, LVI, CxtI))
+static Domain getDomain(const Use &U, LazyValueInfo *LVI) {
+  ConstantRange CR = LVI->getConstantRangeAtUse(U);
+  if (CR.isAllNonNegative())
     return Domain::NonNegative;
-  if (isNonPositive(V, LVI, CxtI))
+  if (CR.icmp(ICmpInst::ICMP_SLE, APInt::getNullValue(CR.getBitWidth())))
     return Domain::NonPositive;
   return Domain::Unknown;
 }
@@ -906,10 +893,9 @@ static bool processSRem(BinaryOperator *SDI, LazyValueInfo *LVI) {
   };
   std::array<Operand, 2> Ops;
 
-  for (const auto I : zip(Ops, SDI->operands())) {
-    Operand &Op = std::get<0>(I);
-    Op.V = std::get<1>(I);
-    Op.D = getDomain(Op.V, LVI, SDI);
+  for (const auto &[Op, U] : zip(Ops, SDI->operands())) {
+    Op.V = U;
+    Op.D = getDomain(U, LVI);
     if (Op.D == Domain::Unknown)
       return false;
   }
@@ -964,10 +950,9 @@ static bool processSDiv(BinaryOperator *SDI, LazyValueInfo *LVI) {
   };
   std::array<Operand, 2> Ops;
 
-  for (const auto I : zip(Ops, SDI->operands())) {
-    Operand &Op = std::get<0>(I);
-    Op.V = std::get<1>(I);
-    Op.D = getDomain(Op.V, LVI, SDI);
+  for (const auto &[Op, U] : zip(Ops, SDI->operands())) {
+    Op.V = U;
+    Op.D = getDomain(U, LVI);
     if (Op.D == Domain::Unknown)
       return false;
   }
@@ -1038,7 +1023,7 @@ static bool processAShr(BinaryOperator *SDI, LazyValueInfo *LVI) {
     return true;
   }
 
-  if (!isNonNegative(SDI->getOperand(0), LVI, SDI))
+  if (!LRange.isAllNonNegative())
     return false;
 
   ++NumAShrsConverted;
@@ -1057,9 +1042,8 @@ static bool processSExt(SExtInst *SDI, LazyValueInfo *LVI) {
   if (SDI->getType()->isVectorTy())
     return false;
 
-  Value *Base = SDI->getOperand(0);
-
-  if (!isNonNegative(Base, LVI, SDI))
+  const Use &Base = SDI->getOperandUse(0);
+  if (!LVI->getConstantRangeAtUse(Base).isAllNonNegative())
     return false;
 
   ++NumSExt;

diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/cond-at-use.ll b/llvm/test/Transforms/CorrelatedValuePropagation/cond-at-use.ll
@@ -425,9 +425,11 @@ define i16 @srem_narrow(i16 %x) {
 
 define i16 @srem_convert(i16 %x) {
 ; CHECK-LABEL: @srem_convert(
-; CHECK-NEXT:    [[SREM:%.*]] = srem i16 [[X:%.*]], 42
+; CHECK-NEXT:    [[X_NONNEG:%.*]] = sub i16 0, [[X:%.*]]
+; CHECK-NEXT:    [[SREM1:%.*]] = urem i16 [[X_NONNEG]], 42
+; CHECK-NEXT:    [[SREM1_NEG:%.*]] = sub i16 0, [[SREM1]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i16 [[X]], 0
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], i16 [[SREM]], i16 24
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], i16 [[SREM1_NEG]], i16 24
 ; CHECK-NEXT:    ret i16 [[SEL]]
 ;
   %srem = srem i16 %x, 42
@@ -438,9 +440,11 @@ define i16 @srem_convert(i16 %x) {
 
 define i16 @sdiv_convert(i16 %x) {
 ; CHECK-LABEL: @sdiv_convert(
-; CHECK-NEXT:    [[SREM:%.*]] = sdiv i16 [[X:%.*]], 42
+; CHECK-NEXT:    [[X_NONNEG:%.*]] = sub i16 0, [[X:%.*]]
+; CHECK-NEXT:    [[SREM1:%.*]] = udiv i16 [[X_NONNEG]], 42
+; CHECK-NEXT:    [[SREM1_NEG:%.*]] = sub i16 0, [[SREM1]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i16 [[X]], 0
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], i16 [[SREM]], i16 24
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], i16 [[SREM1_NEG]], i16 24
 ; CHECK-NEXT:    ret i16 [[SEL]]
 ;
   %srem = sdiv i16 %x, 42
@@ -503,7 +507,7 @@ define i16 @umin_elide(i16 %x) {
 
 define i16 @ashr_convert(i16 %x, i16 %y) {
 ; CHECK-LABEL: @ashr_convert(
-; CHECK-NEXT:    [[ASHR:%.*]] = ashr i16 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[ASHR:%.*]] = lshr i16 [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp sge i16 [[X]], 0
 ; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], i16 [[ASHR]], i16 24
 ; CHECK-NEXT:    ret i16 [[SEL]]
@@ -516,7 +520,7 @@ define i16 @ashr_convert(i16 %x, i16 %y) {
 
 define i32 @sext_convert(i16 %x) {
 ; CHECK-LABEL: @sext_convert(
-; CHECK-NEXT:    [[EXT:%.*]] = sext i16 [[X:%.*]] to i32
+; CHECK-NEXT:    [[EXT:%.*]] = zext i16 [[X:%.*]] to i32
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp sge i16 [[X]], 0
 ; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], i32 [[EXT]], i32 24
 ; CHECK-NEXT:    ret i32 [[SEL]]