From 5cf6f112e67e7d6897ed350d5e029868d0af33bf Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Wed, 14 Aug 2002 23:21:10 +0000
Subject: Implement capability to fold this: uint %test4(int %A, int %B) {
%COND = setlt int %A, %B ; <bool> [#uses=1] %result
= cast bool %COND to uint ; <uint> [#uses=1] ret uint
%result } into a single cast instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3339 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Transforms/Scalar/InstructionCombining.cpp | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
(limited to 'lib')
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 366752f..cc00093 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -476,6 +476,13 @@ Instruction *InstCombiner::visitShiftInst(Instruction &I) {
}
+// isCIntegral - For the purposes of casting, we allow conversion of sizes and
+// stuff as long as the value type acts basically integral like.
+//
+static bool isCIntegral(const Type *Ty) {
+ return Ty->isIntegral() || Ty == Type::BoolTy;
+}
+
// isEliminableCastOfCast - Return true if it is valid to eliminate the CI
// instruction.
//
@@ -488,13 +495,13 @@ static inline bool isEliminableCastOfCast(const CastInst &CI,
// It is legal to eliminate the instruction if casting A->B->A if the sizes
// are identical and the bits don't get reinterpreted (for example
- // int->float->int)
+ // int->float->int would not be allowed)
if (SrcTy == DstTy && SrcTy->isLosslesslyConvertableTo(MidTy))
return true;
// Allow free casting and conversion of sizes as long as the sign doesn't
// change...
- if (SrcTy->isIntegral() && MidTy->isIntegral() && DstTy->isIntegral() &&
+ if (isCIntegral(SrcTy) && isCIntegral(MidTy) && isCIntegral(DstTy) &&
SrcTy->isSigned() == MidTy->isSigned() &&
MidTy->isSigned() == DstTy->isSigned()) {
// Only accept cases where we are either monotonically increasing the type
@@ -503,10 +510,10 @@ static inline bool isEliminableCastOfCast(const CastInst &CI,
unsigned SrcSize = SrcTy->getPrimitiveSize();
unsigned MidSize = MidTy->getPrimitiveSize();
unsigned DstSize = DstTy->getPrimitiveSize();
- if (SrcSize < MidSize && MidSize < DstSize)
+ if (SrcSize <= MidSize && MidSize <= DstSize)
return true;
- if (SrcSize > MidSize && MidSize > DstSize)
+ if (SrcSize >= MidSize && MidSize >= DstSize)
return true;
}
--
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