When passing a huge parameter using the byval mechanism, a long

sequence of loads and stores was being generated to perform the
copy on the x86 targets if the parameter was less than 4 byte
aligned, causing llc to use up vast amounts of memory and time.
Use a "rep movs" form instead.  PR7170.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118260 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/Generic/2010-11-04-BigByval.ll

@@ -0,0 +1,11 @@
+; RUN: llc < %s
+; PR7170
+
+%big = type [131072 x i8]
+
+declare void @foo(%big* byval align 1)
+
+define void @bar(%big* byval align 1 %x) {
+  call void @foo(%big* byval align 1 %x)
+  ret void
+}