From 86876422ef086c9b98da61eee7d917dfe0fc404d Mon Sep 17 00:00:00 2001 From: David Green Date: Mon, 12 Aug 2019 17:39:56 +0000 Subject: [PATCH] [ARM] sext of a load is free This teaches the cost model that the sext or zext of a load is going to be free. Differential Revision: https://reviews.llvm.org/D66006 llvm-svn: 368593 --- llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp | 21 +++++++++++++++++++ llvm/test/Analysis/CostModel/ARM/cast.ll | 28 +++++++++++++------------- 2 files changed, 35 insertions(+), 14 deletions(-) diff --git a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp index f3da1b8..b1868cd 100644 --- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp +++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp @@ -167,6 +167,27 @@ int ARMTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src, if (!SrcTy.isSimple() || !DstTy.isSimple()) return BaseT::getCastInstrCost(Opcode, Dst, Src); + // The extend of a load is free + if (I && isa(I->getOperand(0))) { + static const TypeConversionCostTblEntry LoadConversionTbl[] = { + {ISD::SIGN_EXTEND, MVT::i32, MVT::i16, 0}, + {ISD::ZERO_EXTEND, MVT::i32, MVT::i16, 0}, + {ISD::SIGN_EXTEND, MVT::i32, MVT::i8, 0}, + {ISD::ZERO_EXTEND, MVT::i32, MVT::i8, 0}, + {ISD::SIGN_EXTEND, MVT::i16, MVT::i8, 0}, + {ISD::ZERO_EXTEND, MVT::i16, MVT::i8, 0}, + {ISD::SIGN_EXTEND, MVT::i64, MVT::i32, 1}, + {ISD::ZERO_EXTEND, MVT::i64, MVT::i32, 1}, + {ISD::SIGN_EXTEND, MVT::i64, MVT::i16, 1}, + {ISD::ZERO_EXTEND, MVT::i64, MVT::i16, 1}, + {ISD::SIGN_EXTEND, MVT::i64, MVT::i8, 1}, + {ISD::ZERO_EXTEND, MVT::i64, MVT::i8, 1}, + }; + if (const auto *Entry = ConvertCostTableLookup( + LoadConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) + return Entry->Cost; + } + // Some arithmetic, load and store operations have specific instructions // to cast up/down their types automatically at no extra cost. // TODO: Get these tables to know at least what the related operations are. diff --git a/llvm/test/Analysis/CostModel/ARM/cast.ll b/llvm/test/Analysis/CostModel/ARM/cast.ll index c4ff394..1afbf37 100644 --- a/llvm/test/Analysis/CostModel/ARM/cast.ll +++ b/llvm/test/Analysis/CostModel/ARM/cast.ll @@ -814,15 +814,15 @@ define i32 @load_extends() { ; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %loadv2i16 = load <2 x i16>, <2 x i16>* undef ; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %loadv4i16 = load <4 x i16>, <4 x i16>* undef ; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %loadv2i32 = load <2 x i32>, <2 x i32>* undef -; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r0 = sext i8 %loadi8 to i16 -; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r1 = zext i8 %loadi8 to i16 -; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r2 = sext i8 %loadi8 to i32 -; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r3 = zext i8 %loadi8 to i32 +; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r0 = sext i8 %loadi8 to i16 +; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r1 = zext i8 %loadi8 to i16 +; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r2 = sext i8 %loadi8 to i32 +; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r3 = zext i8 %loadi8 to i32 ; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r4 = sext i8 %loadi8 to i64 ; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r5 = zext i8 %loadi8 to i64 -; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r6 = sext i16 %loadi16 to i32 -; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r7 = zext i16 %loadi16 to i32 -; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 2 for instruction: %r8 = sext i16 %loadi16 to i64 +; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r6 = sext i16 %loadi16 to i32 +; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r7 = zext i16 %loadi16 to i32 +; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r8 = sext i16 %loadi16 to i64 ; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r9 = zext i16 %loadi16 to i64 ; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r10 = sext i32 %loadi32 to i64 ; CHECK-NEON-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r11 = zext i32 %loadi32 to i64 @@ -850,15 +850,15 @@ define i32 @load_extends() { ; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %loadv2i16 = load <2 x i16>, <2 x i16>* undef ; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %loadv4i16 = load <4 x i16>, <4 x i16>* undef ; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %loadv2i32 = load <2 x i32>, <2 x i32>* undef -; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r0 = sext i8 %loadi8 to i16 -; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r1 = zext i8 %loadi8 to i16 -; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r2 = sext i8 %loadi8 to i32 -; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r3 = zext i8 %loadi8 to i32 +; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r0 = sext i8 %loadi8 to i16 +; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r1 = zext i8 %loadi8 to i16 +; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r2 = sext i8 %loadi8 to i32 +; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r3 = zext i8 %loadi8 to i32 ; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r4 = sext i8 %loadi8 to i64 ; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r5 = zext i8 %loadi8 to i64 -; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r6 = sext i16 %loadi16 to i32 -; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r7 = zext i16 %loadi16 to i32 -; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 2 for instruction: %r8 = sext i16 %loadi16 to i64 +; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r6 = sext i16 %loadi16 to i32 +; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %r7 = zext i16 %loadi16 to i32 +; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r8 = sext i16 %loadi16 to i64 ; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r9 = zext i16 %loadi16 to i64 ; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r10 = sext i32 %loadi32 to i64 ; CHECK-MVE-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %r11 = zext i32 %loadi32 to i64 -- 2.7.4