[llvm] r368593 - [ARM] sext of a load is free
David Green via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 12 10:39:56 PDT 2019
Author: dmgreen
Date: Mon Aug 12 10:39:56 2019
New Revision: 368593
URL: http://llvm.org/viewvc/llvm-project?rev=368593&view=rev
Log:
[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
Modified:
llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp
llvm/trunk/test/Analysis/CostModel/ARM/cast.ll
Modified: llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp?rev=368593&r1=368592&r2=368593&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp Mon Aug 12 10:39:56 2019
@@ -167,6 +167,27 @@ int ARMTTIImpl::getCastInstrCost(unsigne
if (!SrcTy.isSimple() || !DstTy.isSimple())
return BaseT::getCastInstrCost(Opcode, Dst, Src);
+ // The extend of a load is free
+ if (I && isa<LoadInst>(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.
Modified: llvm/trunk/test/Analysis/CostModel/ARM/cast.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/CostModel/ARM/cast.ll?rev=368593&r1=368592&r2=368593&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/CostModel/ARM/cast.ll (original)
+++ llvm/trunk/test/Analysis/CostModel/ARM/cast.ll Mon Aug 12 10:39:56 2019
@@ -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
More information about the llvm-commits
mailing list