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Split the main for-each-use loop again, this time for GenerateTruncates, 

as it also peeks at which registers are being used by other uses. This
makes LSR less sensitive to use-list order.

llvm-svn: 96308
This commit is contained in:
Dan Gohman 2010-02-16 01:42:53 +00:00
parent d37e7b5bc5
commit 521efe68ab
2 changed files with 63 additions and 1 deletions
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5
llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@ -2427,7 +2427,7 @@ void LSRInstance::GenerateCrossUseConstantOffsets() {
/// GenerateAllReuseFormulae - Generate formulae for each use.
void
LSRInstance::GenerateAllReuseFormulae() {
// This is split into two loops so that hasRegsUsedByUsesOtherThan
// This is split into multiple loops so that hasRegsUsedByUsesOtherThan
// queries are more precise.
for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) {
LSRUse &LU = Uses[LUIdx];
@ -2446,6 +2446,9 @@ LSRInstance::GenerateAllReuseFormulae() {
GenerateICmpZeroScales(LU, LUIdx, LU.Formulae[i]);
for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i)
GenerateScales(LU, LUIdx, LU.Formulae[i]);
}
for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) {
LSRUse &LU = Uses[LUIdx];
for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i)
GenerateTruncates(LU, LUIdx, LU.Formulae[i]);
}

59
llvm/test/CodeGen/X86/lsr-reuse-trunc.ll Normal file
View File

@ -0,0 +1,59 @@
; RUN: llc < %s -march=x86-64 | FileCheck %s
; Full strength reduction wouldn't reduce register pressure, so LSR should
; stick with indexing here.
; CHECK: movaps (%rsi,%rax,4), %xmm3
; CHECK: movaps %xmm3, (%rdi,%rax,4)
; CHECK: addq $4, %rax
; CHECK: cmpl %eax, (%rdx)
; CHECK-NEXT: jg
define void @vvfloorf(float* nocapture %y, float* nocapture %x, i32* nocapture %n) nounwind {
entry:
%0 = load i32* %n, align 4
%1 = icmp sgt i32 %0, 0
br i1 %1, label %bb, label %return
bb:
%indvar = phi i64 [ %indvar.next, %bb ], [ 0, %entry ]
%tmp = shl i64 %indvar, 2
%scevgep = getelementptr float* %y, i64 %tmp
%scevgep9 = bitcast float* %scevgep to <4 x float>*
%scevgep10 = getelementptr float* %x, i64 %tmp
%scevgep1011 = bitcast float* %scevgep10 to <4 x float>*
%2 = load <4 x float>* %scevgep1011, align 16
%3 = bitcast <4 x float> %2 to <4 x i32>
%4 = and <4 x i32> %3, <i32 2147483647, i32 2147483647, i32 2147483647, i32 2147483647>
%5 = bitcast <4 x i32> %4 to <4 x float>
%6 = and <4 x i32> %3, <i32 -2147483648, i32 -2147483648, i32 -2147483648, i32 -2147483648>
%7 = tail call <4 x float> @llvm.x86.sse.cmp.ps(<4 x float> %5, <4 x float> <float 8.388608e+06, float 8.388608e+06, float 8.388608e+06, float 8.388608e+06>, i8 5) nounwind
%tmp.i4 = bitcast <4 x float> %7 to <4 x i32>
%8 = xor <4 x i32> %tmp.i4, <i32 -1, i32 -1, i32 -1, i32 -1>
%9 = and <4 x i32> %8, <i32 1258291200, i32 1258291200, i32 1258291200, i32 1258291200>
%10 = or <4 x i32> %9, %6
%11 = bitcast <4 x i32> %10 to <4 x float>
%12 = fadd <4 x float> %2, %11
%13 = fsub <4 x float> %12, %11
%14 = tail call <4 x float> @llvm.x86.sse.cmp.ps(<4 x float> %2, <4 x float> %13, i8 1) nounwind
%15 = bitcast <4 x float> %14 to <4 x i32>
%16 = tail call <4 x float> @llvm.x86.sse2.cvtdq2ps(<4 x i32> %15) nounwind readnone
%17 = fadd <4 x float> %13, %16
%tmp.i = bitcast <4 x float> %17 to <4 x i32>
%18 = or <4 x i32> %tmp.i, %6
%19 = bitcast <4 x i32> %18 to <4 x float>
store <4 x float> %19, <4 x float>* %scevgep9, align 16
%tmp12 = add i64 %tmp, 4
%tmp13 = trunc i64 %tmp12 to i32
%20 = load i32* %n, align 4
%21 = icmp sgt i32 %20, %tmp13
%indvar.next = add i64 %indvar, 1
br i1 %21, label %bb, label %return
return:
ret void
}
declare <4 x float> @llvm.x86.sse.cmp.ps(<4 x float>, <4 x float>, i8) nounwind readnone
declare <4 x float> @llvm.x86.sse2.cvtdq2ps(<4 x i32>) nounwind readnone