From 5b73c08896ce402212993ca938f64b056f68e0a1 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 6 Jul 2004 07:01:22 +0000 Subject: [PATCH] Implement InstCombine/sub.ll:test15: X % -Y === X % Y Also, remove X % -1 = 0, because it's not true for unsigneds, and the signed case is superceeded by this new handling. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14637 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/InstructionCombining.cpp | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index c0d0591c9b3..fad2730d84c 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -844,11 +844,18 @@ Instruction *InstCombiner::visitDiv(BinaryOperator &I) { Instruction *InstCombiner::visitRem(BinaryOperator &I) { + if (I.getType()->isSigned()) + if (Value *RHSNeg = dyn_castNegVal(I.getOperand(1))) + if (RHSNeg != I.getOperand(1)) { // Avoid problems with MININT + // X % -Y -> X % Y + AddUsesToWorkList(I); + I.setOperand(1, RHSNeg); + return &I; + } + if (ConstantInt *RHS = dyn_cast(I.getOperand(1))) { if (RHS->equalsInt(1)) // X % 1 == 0 return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); - if (RHS->isAllOnesValue()) // X % -1 == 0 - return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); // Check to see if this is an unsigned remainder with an exact power of 2, // if so, convert to a bitwise and.