On x86-64, for a varargs function, don't store the xmm registers to
the register save area if %al is 0. This avoids touching xmm
regsiters when they aren't actually used.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79061 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/X86/stdarg.ll b/test/CodeGen/X86/stdarg.ll
new file mode 100644
index 0000000..7207057
--- /dev/null
+++ b/test/CodeGen/X86/stdarg.ll
@@ -0,0 +1,20 @@
+; RUN: llvm-as < %s | llc -march=x86-64 | grep {testb \[%\]al, \[%\]al}
+
+%struct.__va_list_tag = type { i32, i32, i8*, i8* }
+
+define void @foo(i32 %x, ...) nounwind {
+entry:
+ %ap = alloca [1 x %struct.__va_list_tag], align 8; <[1 x %struct.__va_list_tag]*> [#uses=2]
+ %ap12 = bitcast [1 x %struct.__va_list_tag]* %ap to i8*; <i8*> [#uses=2]
+ call void @llvm.va_start(i8* %ap12)
+ %ap3 = getelementptr inbounds [1 x %struct.__va_list_tag]* %ap, i64 0, i64 0; <%struct.__va_list_tag*> [#uses=1]
+ call void @bar(%struct.__va_list_tag* %ap3) nounwind
+ call void @llvm.va_end(i8* %ap12)
+ ret void
+}
+
+declare void @llvm.va_start(i8*) nounwind
+
+declare void @bar(%struct.__va_list_tag*)
+
+declare void @llvm.va_end(i8*) nounwind