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When determining the set of interesting reuse factors, consider

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strides in foreign loops. This helps locate reuse opportunities
with existing induction variables in foreign loops and reduces
the need for inserting new ones. This fixes rdar://7657764.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96629 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-02-19 00:05:23 +00:00
parent aa11defd1c
commit 1b7bf18def
2 changed files with 72 additions and 10 deletions
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24
lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@ -1690,21 +1690,29 @@ LSRInstance::getUse(const SCEV *&Expr,
void LSRInstance::CollectInterestingTypesAndFactors() {
SmallSetVector<const SCEV *, 4> Strides;
// Collect interesting types and factors.
// Collect interesting types and strides.
for (IVUsers::const_iterator UI = IU.begin(), E = IU.end(); UI != E; ++UI) {
const SCEV *Stride = UI->getStride();
// Collect interesting types.
Types.insert(SE.getEffectiveSCEVType(Stride->getType()));
// Collect interesting factors.
// Add the stride for this loop.
Strides.insert(Stride);
// Add strides for other mentioned loops.
for (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(UI->getOffset());
AR; AR = dyn_cast<SCEVAddRecExpr>(AR->getStart()))
Strides.insert(AR->getStepRecurrence(SE));
}
// Compute interesting factors from the set of interesting strides.
for (SmallSetVector<const SCEV *, 4>::const_iterator
I = Strides.begin(), E = Strides.end(); I != E; ++I)
for (SmallSetVector<const SCEV *, 4>::const_iterator NewStrideIter =
Strides.begin(), SEnd = Strides.end(); NewStrideIter != SEnd;
++NewStrideIter) {
const SCEV *OldStride = Stride;
next(I); NewStrideIter != E; ++NewStrideIter) {
const SCEV *OldStride = *I;
const SCEV *NewStride = *NewStrideIter;
if (OldStride == NewStride)
continue;
if (SE.getTypeSizeInBits(OldStride->getType()) !=
SE.getTypeSizeInBits(NewStride->getType())) {
@ -1726,8 +1734,6 @@ void LSRInstance::CollectInterestingTypesAndFactors() {
Factors.insert(Factor->getValue()->getValue().getSExtValue());
}
}
Strides.insert(Stride);
}
// If all uses use the same type, don't bother looking for truncation-based
// reuse.

58
test/CodeGen/X86/lsr-reuse.ll
View File

@ -1,4 +1,4 @@
; RUN: llc < %s -march=x86-64 -O3 | FileCheck %s
; RUN: llc < %s -march=x86-64 -O3 -asm-verbose=false | FileCheck %s
target datalayout = "e-p:64:64:64"
target triple = "x86_64-unknown-unknown"
@ -384,3 +384,59 @@ loop:
return:
ret void
}
; LSR should use only one indvar for the inner loop.
; rdar://7657764
; CHECK: asd:
; CHECK: BB10_5:
; CHECK-NEXT: addl (%r{{[^,]*}},%rdi,4), %e
; CHECK-NEXT: incq %rdi
; CHECK-NEXT: cmpq %rdi, %r{{[^,]*}}
; CHECK-NEXT: jg
%struct.anon = type { i32, [4200 x i32] }
@bars = common global [123123 x %struct.anon] zeroinitializer, align 32 ; <[123123 x %struct.anon]*> [#uses=2]
define i32 @asd(i32 %n) nounwind readonly {
entry:
%0 = icmp sgt i32 %n, 0 ; <i1> [#uses=1]
br i1 %0, label %bb.nph14, label %bb5
bb.nph14: ; preds = %entry
%tmp18 = zext i32 %n to i64 ; <i64> [#uses=1]
br label %bb
bb: ; preds = %bb3, %bb.nph14
%indvar16 = phi i64 [ 0, %bb.nph14 ], [ %indvar.next17, %bb3 ] ; <i64> [#uses=3]
%s.113 = phi i32 [ 0, %bb.nph14 ], [ %s.0.lcssa, %bb3 ] ; <i32> [#uses=2]
%scevgep2526 = getelementptr [123123 x %struct.anon]* @bars, i64 0, i64 %indvar16, i32 0 ; <i32*> [#uses=1]
%1 = load i32* %scevgep2526, align 4 ; <i32> [#uses=2]
%2 = icmp sgt i32 %1, 0 ; <i1> [#uses=1]
br i1 %2, label %bb.nph, label %bb3
bb.nph: ; preds = %bb
%tmp23 = sext i32 %1 to i64 ; <i64> [#uses=1]
br label %bb1
bb1: ; preds = %bb.nph, %bb1
%indvar = phi i64 [ 0, %bb.nph ], [ %tmp19, %bb1 ] ; <i64> [#uses=2]
%s.07 = phi i32 [ %s.113, %bb.nph ], [ %4, %bb1 ] ; <i32> [#uses=1]
%c.08 = getelementptr [123123 x %struct.anon]* @bars, i64 0, i64 %indvar16, i32 1, i64 %indvar ; <i32*> [#uses=1]
%3 = load i32* %c.08, align 4 ; <i32> [#uses=1]
%4 = add nsw i32 %3, %s.07 ; <i32> [#uses=2]
%tmp19 = add i64 %indvar, 1 ; <i64> [#uses=2]
%5 = icmp sgt i64 %tmp23, %tmp19 ; <i1> [#uses=1]
br i1 %5, label %bb1, label %bb3
bb3: ; preds = %bb1, %bb
%s.0.lcssa = phi i32 [ %s.113, %bb ], [ %4, %bb1 ] ; <i32> [#uses=2]
%indvar.next17 = add i64 %indvar16, 1 ; <i64> [#uses=2]
%exitcond = icmp eq i64 %indvar.next17, %tmp18 ; <i1> [#uses=1]
br i1 %exitcond, label %bb5, label %bb
bb5: ; preds = %bb3, %entry
%s.1.lcssa = phi i32 [ 0, %entry ], [ %s.0.lcssa, %bb3 ] ; <i32> [#uses=1]
ret i32 %s.1.lcssa
}