[CostModel][X86] Split MUL/SDIV+SREM/UDIV+UREM PowerOf2 handling. NFC.

This is a NFC cleanup to simplify some upcoming refactoring required to address the regressions in D111968.
llvm · Dec 8, 2021 · 30e38d6 · 30e38d6
1 parent 0f865dc
commit 30e38d6
Showing 1 changed file with 38 additions and 35 deletions.
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -236,47 +236,50 @@ InstructionCost X86TTIImpl::getArithmeticInstrCost(
     }
   }
 
-  if ((ISD == ISD::MUL || ISD == ISD::SDIV || ISD == ISD::SREM ||
-       ISD == ISD::UDIV || ISD == ISD::UREM) &&
+  // Vector multiply by pow2 will be simplified to shifts.
+  if (ISD == ISD::MUL &&
+      (Op2Info == TargetTransformInfo::OK_UniformConstantValue ||
+       Op2Info == TargetTransformInfo::OK_NonUniformConstantValue) &&
+      Opd2PropInfo == TargetTransformInfo::OP_PowerOf2)
+    return getArithmeticInstrCost(Instruction::Shl, Ty, CostKind, Op1Info,
+                                  Op2Info, TargetTransformInfo::OP_None,
+                                  TargetTransformInfo::OP_None);
+
+  // On X86, vector signed division by constants power-of-two are
+  // normally expanded to the sequence SRA + SRL + ADD + SRA.
+  // The OperandValue properties may not be the same as that of the previous
+  // operation; conservatively assume OP_None.
+  if ((ISD == ISD::SDIV || ISD == ISD::SREM) &&
       (Op2Info == TargetTransformInfo::OK_UniformConstantValue ||
        Op2Info == TargetTransformInfo::OK_NonUniformConstantValue) &&
       Opd2PropInfo == TargetTransformInfo::OP_PowerOf2) {
-    // Vector multiply by pow2 will be simplified to shifts.
-    if (ISD == ISD::MUL) {
-      InstructionCost Cost = getArithmeticInstrCost(
-          Instruction::Shl, Ty, CostKind, Op1Info, Op2Info,
-          TargetTransformInfo::OP_None, TargetTransformInfo::OP_None);
-      return Cost;
+    InstructionCost Cost =
+        2 * getArithmeticInstrCost(Instruction::AShr, Ty, CostKind, Op1Info,
+                                   Op2Info, TargetTransformInfo::OP_None,
+                                   TargetTransformInfo::OP_None);
+    Cost += getArithmeticInstrCost(Instruction::LShr, Ty, CostKind, Op1Info,
+                                   Op2Info, TargetTransformInfo::OP_None,
+                                   TargetTransformInfo::OP_None);
+    Cost += getArithmeticInstrCost(Instruction::Add, Ty, CostKind, Op1Info,
+                                   Op2Info, TargetTransformInfo::OP_None,
+                                   TargetTransformInfo::OP_None);
+
+    if (ISD == ISD::SREM) {
+      // For SREM: (X % C) is the equivalent of (X - (X/C)*C)
+      Cost += getArithmeticInstrCost(Instruction::Mul, Ty, CostKind, Op1Info,
+                                     Op2Info);
+      Cost += getArithmeticInstrCost(Instruction::Sub, Ty, CostKind, Op1Info,
+                                     Op2Info);
     }
 
-    if (ISD == ISD::SDIV || ISD == ISD::SREM) {
-      // On X86, vector signed division by constants power-of-two are
-      // normally expanded to the sequence SRA + SRL + ADD + SRA.
-      // The OperandValue properties may not be the same as that of the previous
-      // operation; conservatively assume OP_None.
-      InstructionCost Cost =
-          2 * getArithmeticInstrCost(Instruction::AShr, Ty, CostKind, Op1Info,
-                                     Op2Info, TargetTransformInfo::OP_None,
-                                     TargetTransformInfo::OP_None);
-      Cost += getArithmeticInstrCost(Instruction::LShr, Ty, CostKind, Op1Info,
-                                     Op2Info, TargetTransformInfo::OP_None,
-                                     TargetTransformInfo::OP_None);
-      Cost += getArithmeticInstrCost(Instruction::Add, Ty, CostKind, Op1Info,
-                                     Op2Info, TargetTransformInfo::OP_None,
-                                     TargetTransformInfo::OP_None);
-
-      if (ISD == ISD::SREM) {
-        // For SREM: (X % C) is the equivalent of (X - (X/C)*C)
-        Cost += getArithmeticInstrCost(Instruction::Mul, Ty, CostKind, Op1Info,
-                                       Op2Info);
-        Cost += getArithmeticInstrCost(Instruction::Sub, Ty, CostKind, Op1Info,
-                                       Op2Info);
-      }
-
-      return Cost;
-    }
+    return Cost;
+  }
 
-    // Vector unsigned division/remainder will be simplified to shifts/masks.
+  // Vector unsigned division/remainder will be simplified to shifts/masks.
+  if ((ISD == ISD::UDIV || ISD == ISD::UREM) &&
+      (Op2Info == TargetTransformInfo::OK_UniformConstantValue ||
+       Op2Info == TargetTransformInfo::OK_NonUniformConstantValue) &&
+      Opd2PropInfo == TargetTransformInfo::OP_PowerOf2) {
     if (ISD == ISD::UDIV)
       return getArithmeticInstrCost(Instruction::LShr, Ty, CostKind, Op1Info,
                                     Op2Info, TargetTransformInfo::OP_None,