Move some rem transforms out of instcombine and into instsimplify.
This automagically provides a transform noticed by my super-optimizer
as occurring quite often: "rem x, (select cond, x, 1)" -> 0.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130694 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 230b80e..57fb08a 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -492,28 +492,6 @@
return 0;
}
-/// This function implements the transforms on rem instructions that work
-/// regardless of the kind of rem instruction it is (urem, srem, or frem). It
-/// is used by the visitors to those instructions.
-/// @brief Transforms common to all three rem instructions
-Instruction *InstCombiner::commonRemTransforms(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (isa<UndefValue>(Op0)) { // undef % X -> 0
- if (I.getType()->isFPOrFPVectorTy())
- return ReplaceInstUsesWith(I, Op0); // X % undef -> undef (could be SNaN)
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- }
- if (isa<UndefValue>(Op1))
- return ReplaceInstUsesWith(I, Op1); // X % undef -> undef
-
- // Handle cases involving: rem X, (select Cond, Y, Z)
- if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
- return &I;
-
- return 0;
-}
-
/// This function implements the transforms common to both integer remainder
/// instructions (urem and srem). It is called by the visitors to those integer
/// remainder instructions.
@@ -521,26 +499,11 @@
Instruction *InstCombiner::commonIRemTransforms(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Instruction *common = commonRemTransforms(I))
- return common;
-
- // X % X == 0
- if (Op0 == Op1)
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
- // 0 % X == 0 for integer, we don't need to preserve faults!
- if (Constant *LHS = dyn_cast<Constant>(Op0))
- if (LHS->isNullValue())
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
+ // Handle cases involving: rem X, (select Cond, Y, Z)
+ if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
+ return &I;
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // X % 0 == undef, we don't need to preserve faults!
- if (RHS->equalsInt(0))
- return ReplaceInstUsesWith(I, UndefValue::get(I.getType()));
-
- if (RHS->equalsInt(1)) // X % 1 == 0
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) {
if (SelectInst *SI = dyn_cast<SelectInst>(Op0I)) {
if (Instruction *R = FoldOpIntoSelect(I, SI))
@@ -562,6 +525,9 @@
Instruction *InstCombiner::visitURem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyURemInst(Op0, Op1, TD))
+ return ReplaceInstUsesWith(I, V);
+
if (Instruction *common = commonIRemTransforms(I))
return common;
@@ -602,6 +568,9 @@
Instruction *InstCombiner::visitSRem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifySRemInst(Op0, Op1, TD))
+ return ReplaceInstUsesWith(I, V);
+
// Handle the integer rem common cases
if (Instruction *Common = commonIRemTransforms(I))
return Common;
@@ -660,6 +629,14 @@
}
Instruction *InstCombiner::visitFRem(BinaryOperator &I) {
- return commonRemTransforms(I);
-}
+ Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyFRemInst(Op0, Op1, TD))
+ return ReplaceInstUsesWith(I, V);
+
+ // Handle cases involving: rem X, (select Cond, Y, Z)
+ if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
+ return &I;
+
+ return 0;
+}