Optimize alignment of loads and stores.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40102 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 816a1c6..33fd843 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -8790,6 +8790,11 @@
Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
Value *Op = LI.getOperand(0);
+ // Attempt to improve the alignment.
+ unsigned KnownAlign = GetKnownAlignment(Op, TD);
+ if (KnownAlign > LI.getAlignment())
+ LI.setAlignment(KnownAlign);
+
// load (cast X) --> cast (load X) iff safe
if (isa<CastInst>(Op))
if (Instruction *Res = InstCombineLoadCast(*this, LI))
@@ -8985,6 +8990,11 @@
}
}
+ // Attempt to improve the alignment.
+ unsigned KnownAlign = GetKnownAlignment(Ptr, TD);
+ if (KnownAlign > SI.getAlignment())
+ SI.setAlignment(KnownAlign);
+
// Do really simple DSE, to catch cases where there are several consequtive
// stores to the same location, separated by a few arithmetic operations. This
// situation often occurs with bitfield accesses.