Merging r197492:
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r197492 | dyatkovskiy | 2013-12-17 04:07:33 -0800 (Tue, 17 Dec 2013) | 26 lines
Fix for PR18045:
http://llvm.org/bugs/show_bug.cgi?id=18045
Short issue description:
For X86 machines with sse < sse4.1 we got failures for some
particular load/store vector sequences:
$ clang-trunk -m32 -O2 test-case.c
fatal error: error in backend: Cannot select: 0x4200920: v4i32,ch = load 0x41d6ab0, 0x4205850,
0x41dcb10<LD16[getelementptr inbounds ([4 x i32]* @e, i32 0, i32 0)](align=4)> [ORD=82]
[ID=58]
0x4205850: i32 = X86ISD::Wrapper 0x41d5490 [ORD=26] [ID=43]
0x41d5490: i32 = TargetGlobalAddress<[4 x i32]* @e> 0 [ORD=26] [ID=23]
0x41dcb10: i32 = undef [ID=2]
The reason is that EltsFromConsecutiveLoads could emit such load instruction
both before and after legalize stage. Though this instruction is not legal for
machines with SSSE3 and lower.
The fix: In EltsFromConsecutiveLoads, if we have passed legalize stage, we
check whether nodes it emits are legal.
P.S.: If you get failure in time from 12:00 and till 22:00 (UTC-8),
perhaps I'll slow with response, so you better reject this commit. Thanks!
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_34@197779 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index d0667ff..76eeb64 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -5395,7 +5395,8 @@
/// rather than undef via VZEXT_LOAD, but we do not detect that case today.
/// There's even a handy isZeroNode for that purpose.
static SDValue EltsFromConsecutiveLoads(EVT VT, SmallVectorImpl<SDValue> &Elts,
- SDLoc &DL, SelectionDAG &DAG) {
+ SDLoc &DL, SelectionDAG &DAG,
+ bool isAfterLegalize) {
EVT EltVT = VT.getVectorElementType();
unsigned NumElems = Elts.size();
@@ -5431,7 +5432,13 @@
// load of the entire vector width starting at the base pointer. If we found
// consecutive loads for the low half, generate a vzext_load node.
if (LastLoadedElt == NumElems - 1) {
+
+ if (isAfterLegalize &&
+ !DAG.getTargetLoweringInfo().isOperationLegal(ISD::LOAD, VT))
+ return SDValue();
+
SDValue NewLd = SDValue();
+
if (DAG.InferPtrAlignment(LDBase->getBasePtr()) >= 16)
NewLd = DAG.getLoad(VT, DL, LDBase->getChain(), LDBase->getBasePtr(),
LDBase->getPointerInfo(),
@@ -6075,7 +6082,7 @@
V[i] = Op.getOperand(i);
// Check for elements which are consecutive loads.
- SDValue LD = EltsFromConsecutiveLoads(VT, V, dl, DAG);
+ SDValue LD = EltsFromConsecutiveLoads(VT, V, dl, DAG, false);
if (LD.getNode())
return LD;
@@ -16263,7 +16270,7 @@
for (unsigned i = 0, e = VT.getVectorNumElements(); i != e; ++i)
Elts.push_back(getShuffleScalarElt(N, i, DAG, 0));
- return EltsFromConsecutiveLoads(VT, Elts, dl, DAG);
+ return EltsFromConsecutiveLoads(VT, Elts, dl, DAG, true);
}
/// PerformTruncateCombine - Converts truncate operation to