RPCSX/llvm
1
0
Fork 0
mirror of https://github.com/RPCSX/llvm.git synced 2025-01-27 07:12:06 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[InstCombine] insert a new shuffle before its uses (PR26015)

Browse Source 
Although this solves the test case in PR26015:
https://llvm.org/bugs/show_bug.cgi?id=26015

And may solve PR25999:
https://llvm.org/bugs/show_bug.cgi?id=25999

...I suspect this is not the best solution. I think we want to insert the new shuffle
just ahead of the earliest ExtractElementInst that we're replacing, but I don't know 
how that should be implemented.

Differential Revision: http://reviews.llvm.org/D15878



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256857 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sanjay Patel 2016-01-05 19:09:47 +00:00
parent db61103ea8
commit 7a3b692c47
2 changed files with 74 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
lib/Transforms/InstCombine/InstCombineVectorOps.cpp
View File

@ -383,15 +383,28 @@ static void replaceExtractElements(InsertElementInst *InsElt,
auto *WideVec = new ShuffleVectorInst(ExtVecOp, UndefValue::get(ExtVecType),
ConstantVector::get(ExtendMask));
// Replace all extracts from the original narrow vector with extracts from
// the new wide vector.
WideVec->insertBefore(ExtElt);
// Insert the new shuffle after the vector operand of the extract is defined
// or at the start of the basic block, so any subsequent extracts can use it.
bool ReplaceAllExtUsers;
if (auto *ExtVecOpInst = dyn_cast<Instruction>(ExtVecOp)) {
WideVec->insertAfter(ExtVecOpInst);
ReplaceAllExtUsers = true;
} else {
// TODO: Insert at start of function, so it's always safe to replace all?
IC.InsertNewInstWith(WideVec, *ExtElt->getParent()->getFirstInsertionPt());
ReplaceAllExtUsers = false;
}
// Replace extracts from the original narrow vector with extracts from the new
// wide vector.
for (User *U : ExtVecOp->users()) {
if (ExtractElementInst *OldExt = dyn_cast<ExtractElementInst>(U)) {
auto *NewExt = ExtractElementInst::Create(WideVec, OldExt->getOperand(1));
NewExt->insertAfter(WideVec);
IC.ReplaceInstUsesWith(*OldExt, NewExt);
}
ExtractElementInst *OldExt = dyn_cast<ExtractElementInst>(U);
if (!OldExt ||
(!ReplaceAllExtUsers && OldExt->getParent() != WideVec->getParent()))
continue;
auto *NewExt = ExtractElementInst::Create(WideVec, OldExt->getOperand(1));
NewExt->insertAfter(WideVec);
IC.ReplaceInstUsesWith(*OldExt, NewExt);
}
}

53
test/Transforms/InstCombine/insert-extract-shuffle.ll
View File

@ -72,3 +72,56 @@ define <8 x float> @widen_extract4(<8 x float> %ins, <2 x float> %ext) {
ret <8 x float> %i1
}
; PR26015: https://llvm.org/bugs/show_bug.cgi?id=26015
; The widening shuffle must be inserted before any uses.
define <8 x i16> @pr26015(<4 x i16> %t0) {
; CHECK-LABEL: @pr26015(
; CHECK-NEXT: %[[WIDEVEC:.*]] = shufflevector <4 x i16> %t0, <4 x i16> undef, <8 x i32> <i32 undef, i32 undef, i32 undef, i32 3, i32 undef, i32 undef, i32 undef, i32 undef>
; CHECK-NEXT: %[[EXT:.*]] = extractelement <4 x i16> %t0, i32 2
; CHECK-NEXT: %t2 = insertelement <8 x i16> <i16 0, i16 0, i16 0, i16 undef, i16 0, i16 0, i16 undef, i16 undef>, i16 %[[EXT]], i32 3
; CHECK-NEXT: %t3 = insertelement <8 x i16> %t2, i16 0, i32 6
; CHECK-NEXT: %t5 = shufflevector <8 x i16> %t3, <8 x i16> %[[WIDEVEC]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 11>
; CHECK-NEXT: ret <8 x i16> %t5
%t1 = extractelement <4 x i16> %t0, i32 2
%t2 = insertelement <8 x i16> zeroinitializer, i16 %t1, i32 3
%t3 = insertelement <8 x i16> %t2, i16 0, i32 6
%t4 = extractelement <4 x i16> %t0, i32 3
%t5 = insertelement <8 x i16> %t3, i16 %t4, i32 7
ret <8 x i16> %t5
}
; PR25999: https://llvm.org/bugs/show_bug.cgi?id=25999
; TODO: The widening shuffle could be inserted at the start of the function to allow the first extract to use it.
define <8 x i16> @pr25999(<4 x i16> %t0, i1 %b) {
; CHECK-LABEL: @pr25999(
; CHECK-NEXT: %t1 = extractelement <4 x i16> %t0, i32 2
; CHECK-NEXT: br i1 %b, label %if, label %end
; CHECK: if:
; CHECK-NEXT: %[[WIDEVEC:.*]] = shufflevector <4 x i16> %t0, <4 x i16> undef, <8 x i32> <i32 undef, i32 undef, i32 undef, i32 3, i32 undef, i32 undef, i32 undef, i32 undef>
; CHECK-NEXT: %t2 = insertelement <8 x i16> <i16 0, i16 0, i16 0, i16 undef, i16 0, i16 0, i16 undef, i16 undef>, i16 %t1, i32 3
; CHECK-NEXT: %t3 = insertelement <8 x i16> %t2, i16 0, i32 6
; CHECK-NEXT: %t5 = shufflevector <8 x i16> %t3, <8 x i16> %[[WIDEVEC]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 11>
; CHECK-NEXT: ret <8 x i16> %t5
; CHECK: end:
; CHECK-NEXT: %a1 = add i16 %t1, 4
; CHECK-NEXT: %t6 = insertelement <8 x i16> <i16 undef, i16 0, i16 0, i16 0, i16 0, i16 0, i16 0, i16 0>, i16 %a1, i32 0
; CHECK-NEXT: ret <8 x i16> %t6
%t1 = extractelement <4 x i16> %t0, i32 2
br i1 %b, label %if, label %end
if:
%t2 = insertelement <8 x i16> zeroinitializer, i16 %t1, i32 3
%t3 = insertelement <8 x i16> %t2, i16 0, i32 6
%t4 = extractelement <4 x i16> %t0, i32 3
%t5 = insertelement <8 x i16> %t3, i16 %t4, i32 7
ret <8 x i16> %t5
end:
%a1 = add i16 %t1, 4
%t6 = insertelement <8 x i16> zeroinitializer, i16 %a1, i32 0
ret <8 x i16> %t6
}