[PowerPC] Prefetching should also consider depth > 1 loops

Iterating over loops from the LoopInfo instance only provides top-level loops.
We need to search the whole tree of loops to find the inner ones.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234603 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2015-04-10 15:05:02 +00:00
parent e749325463
commit d4f643a5df
2 changed files with 71 additions and 2 deletions

View File

@ -14,6 +14,7 @@
#define DEBUG_TYPE "ppc-loop-data-prefetch" #define DEBUG_TYPE "ppc-loop-data-prefetch"
#include "PPC.h" #include "PPC.h"
#include "llvm/Transforms/Scalar.h" #include "llvm/Transforms/Scalar.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h" #include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AssumptionCache.h" #include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/CodeMetrics.h" #include "llvm/Analysis/CodeMetrics.h"
@ -110,8 +111,10 @@ bool PPCLoopDataPrefetch::runOnFunction(Function &F) {
bool MadeChange = false; bool MadeChange = false;
for (LoopInfo::iterator I = LI->begin(), E = LI->end(); if (LI->empty())
I != E; ++I) { return MadeChange;
for (auto I = df_begin(*LI->begin()), E = df_end(*LI->begin()); I != E; ++I) {
Loop *L = *I; Loop *L = *I;
MadeChange |= runOnLoop(L); MadeChange |= runOnLoop(L);
} }

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@ -0,0 +1,66 @@
; RUN: llc < %s | FileCheck %s
target datalayout = "E-m:e-i64:64-n32:64"
target triple = "powerpc64-bgq-linux"
; Function Attrs: nounwind
define void @foo(double* %x, double* nocapture readonly %y) #0 {
entry:
%scevgep = getelementptr double, double* %x, i64 1599
%scevgep20 = getelementptr double, double* %y, i64 1599
br label %vector.memcheck
vector.memcheck: ; preds = %for.end, %entry
%j.015 = phi i32 [ 0, %entry ], [ %inc7, %for.end ]
%bound0 = icmp uge double* %scevgep20, %x
%bound1 = icmp uge double* %scevgep, %y
%memcheck.conflict = and i1 %bound0, %bound1
br i1 %memcheck.conflict, label %middle.block, label %vector.body
vector.body: ; preds = %vector.memcheck, %vector.body
%index = phi i64 [ %index.next, %vector.body ], [ 0, %vector.memcheck ]
%0 = getelementptr inbounds double, double* %y, i64 %index
%1 = bitcast double* %0 to <4 x double>*
%wide.load = load <4 x double>, <4 x double>* %1, align 8
%2 = fadd <4 x double> %wide.load, <double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00>
%3 = getelementptr inbounds double, double* %x, i64 %index
%4 = bitcast double* %3 to <4 x double>*
store <4 x double> %2, <4 x double>* %4, align 8
%index.next = add i64 %index, 4
%5 = icmp eq i64 %index.next, 1600
br i1 %5, label %middle.block, label %vector.body
middle.block: ; preds = %vector.body, %vector.memcheck
%resume.val = phi i1 [ false, %vector.memcheck ], [ true, %vector.body ]
%trunc.resume.val = phi i64 [ 0, %vector.memcheck ], [ 1600, %vector.body ]
br i1 %resume.val, label %for.end, label %for.body3
for.body3: ; preds = %middle.block, %for.body3
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body3 ], [ %trunc.resume.val, %middle.block ]
%arrayidx = getelementptr inbounds double, double* %y, i64 %indvars.iv
%6 = load double, double* %arrayidx, align 8
%add = fadd double %6, 1.000000e+00
%arrayidx5 = getelementptr inbounds double, double* %x, i64 %indvars.iv
store double %add, double* %arrayidx5, align 8
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp eq i64 %indvars.iv.next, 1600
br i1 %exitcond, label %for.end, label %for.body3
for.end: ; preds = %middle.block, %for.body3
tail call void @bar(double* %x) #2
%inc7 = add nuw nsw i32 %j.015, 1
%exitcond16 = icmp eq i32 %inc7, 100
br i1 %exitcond16, label %for.end8, label %vector.memcheck
for.end8: ; preds = %for.end
ret void
; CHECK-LABEL: @foo
; CHECK: dcbt
}
declare void @bar(double*) #1
attributes #0 = { nounwind "target-cpu"="a2q" }
attributes #1 = { "target-cpu"="a2q" }
attributes #2 = { nounwind }