Teach basicaa that memset's modref set is at worst "mod" and never
contains "ref".
Enhance DSE to use a modref query instead of a store-specific hack
to generalize the "ignore may-alias stores" optimization to handle
memset and memcpy.
llvm-svn: 120368
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index bf1b689..3e63424 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -703,6 +703,8 @@
if (isNoAlias(Location(Dest, Len), Loc))
return NoModRef;
}
+ // We know that memset doesn't load anything.
+ Min = Mod;
break;
case Intrinsic::atomic_cmp_swap:
case Intrinsic::atomic_swap: