[llvm-commits] [llvm] r167170 - in /llvm/trunk: lib/Target/TargetTransformImpl.cpp test/Transforms/LoopVectorize/X86/conversion-cost.ll
Nadav Rotem
nrotem at apple.com
Wed Oct 31 13:52:26 PDT 2012
Author: nadav
Date: Wed Oct 31 15:52:26 2012
New Revision: 167170
URL: http://llvm.org/viewvc/llvm-project?rev=167170&view=rev
Log:
Fix a bug in the cost calculation of vector casts. Detect situations where bitcasts cost zero.
Added:
llvm/trunk/test/Transforms/LoopVectorize/X86/conversion-cost.ll
Modified:
llvm/trunk/lib/Target/TargetTransformImpl.cpp
Modified: llvm/trunk/lib/Target/TargetTransformImpl.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/TargetTransformImpl.cpp?rev=167170&r1=167169&r2=167170&view=diff
==============================================================================
--- llvm/trunk/lib/Target/TargetTransformImpl.cpp (original)
+++ llvm/trunk/lib/Target/TargetTransformImpl.cpp Wed Oct 31 15:52:26 2012
@@ -211,40 +211,55 @@
std::pair<unsigned, EVT> DstLT =
getTypeLegalizationCost(Dst->getContext(), TLI->getValueType(Dst));
- // If the cast is between same-sized registers, then the check is simple.
- if (SrcLT.first == DstLT.first &&
- SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) {
- // Just check the op cost:
- if (!TLI->isOperationExpand(ISD, DstLT.second)) {
- // The operation is legal. Assume it costs 1. Multiply
- // by the type-legalization overhead.
- return SrcLT.first * 1;
+ // Handle scalar conversions.
+ if (!Src->isVectorTy() && !Dst->isVectorTy()) {
+ // Just check the op cost. If the operation is legal then assume it costs 1.
+ if (!TLI->isOperationExpand(ISD, DstLT.second))
+ return 1;
+
+ // Assume that illegal scalar instruction are expensive.
+ return 4;
+ }
+
+ // Check vector-to-vector casts.
+ if (Dst->isVectorTy() && Src->isVectorTy()) {
+
+ // If the cast is between same-sized registers, then the check is simple.
+ if (SrcLT.first == DstLT.first &&
+ SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) {
+
+ // Bitcast between types that are legalized to the same type are free.
+ if (Opcode == Instruction::BitCast)
+ return 0;
+
+ // Just check the op cost. If the operation is legal then assume it costs
+ // 1 and multiply by the type-legalization overhead.
+ if (!TLI->isOperationExpand(ISD, DstLT.second))
+ return SrcLT.first * 1;
}
- }
-
- unsigned ScalarizationCost = 1;
- // Otherwise, assume that the cast is scalarized.
- if (Dst->isVectorTy()) {
+ // If we are converting vectors and the operation is illegal, or
+ // if the vectors are legalized to different types, estimate the
+ // scalarization costs.
unsigned Num = Dst->getVectorNumElements();
- unsigned Cost = getCastInstrCost(Opcode, Src->getScalarType(),
- Dst->getScalarType());
- // return the cost of multiple scalar invocation plus the cost of inserting
- // and extracting the values.
- ScalarizationCost *= getScalarizationOverhead(Dst, true, true) + Num * Cost;
- }
-
- if (Src->isVectorTy()) {
- unsigned Num = Src->getVectorNumElements();
unsigned Cost = getCastInstrCost(Opcode, Dst->getScalarType(),
Src->getScalarType());
- // return the cost of multiple scalar invocation plus the cost of inserting
- // and extracting the values.
- ScalarizationCost *= getScalarizationOverhead(Src, true, true) + Num * Cost;
+
+ // Return the cost of multiple scalar invocation plus the cost of
+ // inserting and extracting the values.
+ return getScalarizationOverhead(Dst, true, true) + Num * Cost;
}
- return ScalarizationCost;
-}
+ // We already handled vector-to-vector and scalar-to-scalar conversions. This
+ // is where we handle bitcast between vectors and scalars. We need to assume
+ // that the conversion is scalarized in one way or another.
+ if (Opcode == Instruction::BitCast)
+ // Illegal bitcasts are done by storing and loading from a stack slot.
+ return (Src->isVectorTy()? getScalarizationOverhead(Src, false, true):0) +
+ (Dst->isVectorTy()? getScalarizationOverhead(Dst, true, false):0);
+
+ llvm_unreachable("Unhandled cast");
+ }
unsigned VectorTargetTransformImpl::getCFInstrCost(unsigned Opcode) const {
return 1;
Added: llvm/trunk/test/Transforms/LoopVectorize/X86/conversion-cost.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/X86/conversion-cost.ll?rev=167170&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/X86/conversion-cost.ll (added)
+++ llvm/trunk/test/Transforms/LoopVectorize/X86/conversion-cost.ll Wed Oct 31 15:52:26 2012
@@ -0,0 +1,48 @@
+; RUN: opt < %s -loop-vectorize -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -S | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+
+;CHECK: @conversion_cost1
+;CHECK: store <8 x i8>
+;CHECK: ret
+define i32 @conversion_cost1(i32 %n, i8* nocapture %A, float* nocapture %B) nounwind uwtable ssp {
+ %1 = icmp sgt i32 %n, 3
+ br i1 %1, label %.lr.ph, label %._crit_edge
+
+.lr.ph: ; preds = %0, %.lr.ph
+ %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 3, %0 ]
+ %2 = trunc i64 %indvars.iv to i8
+ %3 = getelementptr inbounds i8* %A, i64 %indvars.iv
+ store i8 %2, i8* %3, align 1
+ %indvars.iv.next = add i64 %indvars.iv, 1
+ %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+ %exitcond = icmp eq i32 %lftr.wideiv, %n
+ br i1 %exitcond, label %._crit_edge, label %.lr.ph
+
+._crit_edge: ; preds = %.lr.ph, %0
+ ret i32 undef
+}
+
+;CHECK: @conversion_cost2
+;CHECK: store <8 x float>
+;CHECK: ret
+define i32 @conversion_cost2(i32 %n, i8* nocapture %A, float* nocapture %B) nounwind uwtable ssp {
+ %1 = icmp sgt i32 %n, 9
+ br i1 %1, label %.lr.ph, label %._crit_edge
+
+.lr.ph: ; preds = %0, %.lr.ph
+ %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 9, %0 ]
+ %2 = add nsw i64 %indvars.iv, 3
+ %3 = trunc i64 %2 to i32
+ %4 = sitofp i32 %3 to float
+ %5 = getelementptr inbounds float* %B, i64 %indvars.iv
+ store float %4, float* %5, align 4
+ %indvars.iv.next = add i64 %indvars.iv, 1
+ %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+ %exitcond = icmp eq i32 %lftr.wideiv, %n
+ br i1 %exitcond, label %._crit_edge, label %.lr.ph
+
+._crit_edge: ; preds = %.lr.ph, %0
+ ret i32 undef
+}
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