diff options
author | Evan Cheng <evan.cheng@apple.com> | 2011-11-28 22:37:34 +0000 |
---|---|---|
committer | Evan Cheng <evan.cheng@apple.com> | 2011-11-28 22:37:34 +0000 |
commit | ed1c0c7f5817be939872b462be984534bd48bb9b (patch) | |
tree | ef53597756cecb7f5cfd90c2e9359194a9497a86 | |
parent | a483fc8e6f9533317f517f2d03f3a41ec0aee663 (diff) | |
download | external_llvm-ed1c0c7f5817be939872b462be984534bd48bb9b.zip external_llvm-ed1c0c7f5817be939872b462be984534bd48bb9b.tar.gz external_llvm-ed1c0c7f5817be939872b462be984534bd48bb9b.tar.bz2 |
Revert r145273 and fix in SelectionDAG::InferPtrAlignment() instead.
Conservatively returns zero when the GV does not specify an alignment nor is it
initialized. Previously it returns ABI alignment for type of the GV. However, if
the type is a "packed" type, then the under-specified alignments is attached to
the load / store instructions. In that case, the alignment of the type cannot be
trusted.
rdar://10464621
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145300 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 38 | ||||
-rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 6 | ||||
-rw-r--r-- | test/CodeGen/X86/widen_load-1.ll | 2 |
3 files changed, 18 insertions, 28 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 2c4886a..d8208a4 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -6206,20 +6206,13 @@ SDValue DAGCombiner::visitLOAD(SDNode *N) { // Try to infer better alignment information than the load already has. if (OptLevel != CodeGenOpt::None && LD->isUnindexed()) { - unsigned ABIAlign = TLI.getTargetData()-> - getABITypeAlignment(LD->getMemoryVT().getTypeForEVT(*DAG.getContext())); - unsigned LDAlign = LD->getAlignment(); - // Do not touch loads with explicit alignments that are smaller than ABI - // alignment to avoid breaking loads from "packed" types. - if (!LDAlign || LDAlign >= ABIAlign) { - if (unsigned Align = DAG.InferPtrAlignment(Ptr)) { - if (Align > LDAlign) - return DAG.getExtLoad(LD->getExtensionType(), N->getDebugLoc(), - LD->getValueType(0), - Chain, Ptr, LD->getPointerInfo(), - LD->getMemoryVT(), - LD->isVolatile(), LD->isNonTemporal(), Align); - } + if (unsigned Align = DAG.InferPtrAlignment(Ptr)) { + if (Align > LD->getAlignment()) + return DAG.getExtLoad(LD->getExtensionType(), N->getDebugLoc(), + LD->getValueType(0), + Chain, Ptr, LD->getPointerInfo(), + LD->getMemoryVT(), + LD->isVolatile(), LD->isNonTemporal(), Align); } } @@ -6676,18 +6669,11 @@ SDValue DAGCombiner::visitSTORE(SDNode *N) { // Try to infer better alignment information than the store already has. if (OptLevel != CodeGenOpt::None && ST->isUnindexed()) { - unsigned ABIAlign = TLI.getTargetData()-> - getABITypeAlignment(ST->getMemoryVT().getTypeForEVT(*DAG.getContext())); - unsigned STAlign = ST->getAlignment(); - // Do not touch stores with explicit alignments that are smaller than ABI - // alignment to avoid breaking stores from "packed" types. - if (!STAlign || STAlign >= ABIAlign) { - if (unsigned Align = DAG.InferPtrAlignment(Ptr)) { - if (Align > STAlign) - return DAG.getTruncStore(Chain, N->getDebugLoc(), Value, - Ptr, ST->getPointerInfo(), ST->getMemoryVT(), - ST->isVolatile(), ST->isNonTemporal(),Align); - } + if (unsigned Align = DAG.InferPtrAlignment(Ptr)) { + if (Align > ST->getAlignment()) + return DAG.getTruncStore(Chain, N->getDebugLoc(), Value, + Ptr, ST->getPointerInfo(), ST->getMemoryVT(), + ST->isVolatile(), ST->isNonTemporal(), Align); } } diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index a772a46..024a163 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -6564,7 +6564,11 @@ unsigned SelectionDAG::InferPtrAlignment(SDValue Ptr) const { } } if (!Align) - Align = TLI.getTargetData()->getABITypeAlignment(GV->getType()); + // Conservatively returns zero here instead of using ABI alignment for + // type of the GV. If the type is a "packed" type, then the under- + // specified alignments is attached to the load / store instructions. + // In that case, the alignment of the type cannot be trusted. + return 0; } return MinAlign(Align, GVOffset); } diff --git a/test/CodeGen/X86/widen_load-1.ll b/test/CodeGen/X86/widen_load-1.ll index a9fd1904..9705d14 100644 --- a/test/CodeGen/X86/widen_load-1.ll +++ b/test/CodeGen/X86/widen_load-1.ll @@ -21,7 +21,7 @@ define void @reset(<2 x float>* noalias %garbage1) { store i32 0, i32* %changed, align 4 %r2 = getelementptr float* bitcast ([20 x i64]* @compl to float*), i64 32 ; <float*> [#uses=1] %r3 = bitcast float* %r2 to <2 x float>* ; <<2 x float>*> [#uses=1] - %r4 = load <2 x float>* %r3, align 8 ; <<2 x float>> [#uses=1] + %r4 = load <2 x float>* %r3, align 4 ; <<2 x float>> [#uses=1] call void @killcommon(i32* %changed) br label %"file complex.c, line 34, bb4" |