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[Inliner] Preserve llvm.mem.parallel_loop_access metadata 

When inlining a call site with llvm.mem.parallel_loop_access metadata, this
metadata needs to be propagated to all cloned memory-accessing instructions.
Otherwise, inlining parts of the loop body will invalidate the annotation.

With this functionality, we now vectorize the following as expected:

  void Body(int *res, int *c, int *d, int *p, int i) {
    res[i] = (p[i] == 0) ? res[i] : res[i] + d[i];
  }

  void Test(int *res, int *c, int *d, int *p, int n) {
    int i;

  #pragma clang loop vectorize(assume_safety)
    for (i = 0; i < 1600; i++) {
      Body(res, c, d, p, i);
    }
  }

llvm-svn: 267949
This commit is contained in:
Hal Finkel 2016-04-28 23:00:04 +00:00
parent 70e70e6eb9
commit 50316d95a9
2 changed files with 88 additions and 0 deletions
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31
llvm/lib/Transforms/Utils/InlineFunction.cpp
View File

@ -688,6 +688,34 @@ static void HandleInlinedEHPad(InvokeInst *II, BasicBlock *FirstNewBlock,
UnwindDest->removePredecessor(InvokeBB);
}
/// When inlining a call site that has !llvm.mem.parallel_loop_access metadata,
/// that metadata should be propagated to all memory-accessing cloned
/// instructions.
static void PropagateParallelLoopAccessMetadata(CallSite CS,
ValueToValueMapTy &VMap) {
MDNode *M =
CS.getInstruction()->getMetadata(LLVMContext::MD_mem_parallel_loop_access);
if (!M)
return;
for (ValueToValueMapTy::iterator VMI = VMap.begin(), VMIE = VMap.end();
VMI != VMIE; ++VMI) {
if (!VMI->second)
continue;
Instruction *NI = dyn_cast<Instruction>(VMI->second);
if (!NI)
continue;
if (MDNode *PM = NI->getMetadata(LLVMContext::MD_mem_parallel_loop_access)) {
M = MDNode::concatenate(PM, M);
NI->setMetadata(LLVMContext::MD_mem_parallel_loop_access, M);
} else if (NI->mayReadOrWriteMemory()) {
NI->setMetadata(LLVMContext::MD_mem_parallel_loop_access, M);
}
}
}
/// When inlining a function that contains noalias scope metadata,
/// this metadata needs to be cloned so that the inlined blocks
/// have different "unqiue scopes" at every call site. Were this not done, then
@ -1574,6 +1602,9 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
// Add noalias metadata if necessary.
AddAliasScopeMetadata(CS, VMap, DL, CalleeAAR);
// Propagate llvm.mem.parallel_loop_access if necessary.
PropagateParallelLoopAccessMetadata(CS, VMap);
// FIXME: We could register any cloned assumptions instead of clearing the
// whole function's cache.
if (IFI.ACT)

57
llvm/test/Transforms/Inline/parallel-loop-md.ll Normal file
View File

@ -0,0 +1,57 @@
; RUN: opt -S -inline < %s | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: norecurse nounwind uwtable
define void @Body(i32* nocapture %res, i32* nocapture readnone %c, i32* nocapture readonly %d, i32* nocapture readonly %p, i32 %i) #0 {
entry:
%idxprom = sext i32 %i to i64
%arrayidx = getelementptr inbounds i32, i32* %p, i64 %idxprom
%0 = load i32, i32* %arrayidx, align 4
%cmp = icmp eq i32 %0, 0
%arrayidx2 = getelementptr inbounds i32, i32* %res, i64 %idxprom
%1 = load i32, i32* %arrayidx2, align 4
br i1 %cmp, label %cond.end, label %cond.false
cond.false: ; preds = %entry
%arrayidx6 = getelementptr inbounds i32, i32* %d, i64 %idxprom
%2 = load i32, i32* %arrayidx6, align 4
%add = add nsw i32 %2, %1
br label %cond.end
cond.end: ; preds = %entry, %cond.false
%cond = phi i32 [ %add, %cond.false ], [ %1, %entry ]
store i32 %cond, i32* %arrayidx2, align 4
ret void
}
; Function Attrs: nounwind uwtable
define void @Test(i32* %res, i32* %c, i32* %d, i32* %p, i32 %n) #1 {
entry:
br label %for.cond
for.cond: ; preds = %for.body, %entry
%i.0 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
%cmp = icmp slt i32 %i.0, 1600
br i1 %cmp, label %for.body, label %for.end
for.body: ; preds = %for.cond
call void @Body(i32* %res, i32* undef, i32* %d, i32* %p, i32 %i.0), !llvm.mem.parallel_loop_access !0
%inc = add nsw i32 %i.0, 1
br label %for.cond, !llvm.loop !0
for.end: ; preds = %for.cond
ret void
}
; CHECK-LABEL: @Test
; CHECK: load i32,{{.*}}, !llvm.mem.parallel_loop_access !0
; CHECK: load i32,{{.*}}, !llvm.mem.parallel_loop_access !0
; CHECK: load i32,{{.*}}, !llvm.mem.parallel_loop_access !0
; CHECK: store i32{{.*}}, !llvm.mem.parallel_loop_access !0
; CHECK: br label %for.cond, !llvm.loop !0
attributes #0 = { norecurse nounwind uwtable }
!0 = distinct !{!0}