Simplification of libcall like printf->puts must check for RtLibUseGOT metadata.

With -fno-plt, for example, calls to printf when getting converted to puts
still use the PLT. This patch checks for the metadata "RtLibUseGOT" and
annotates the declaration with the right attributes.

Differential Revision: https://reviews.llvm.org/D45180

llvm-svn: 329768

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/no-plt-libcalls.ll b/llvm/test/CodeGen/X86/no-plt-libcalls.ll
new file mode 100644
index 00000000000..795ad57f9a5
--- /dev/null
+++ b/llvm/test/CodeGen/X86/no-plt-libcalls.ll
@@ -0,0 +1,19 @@
+; Check if "RtLibUseGOT" works correctly when lib calls are simplified.
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+@percent_s = constant [4 x i8] c"%s\0A\00"
+@hello_world = constant [13 x i8] c"hello world\0A\00"
+declare i32 @printf(i8*, ...)
+define void @printf_call() {
+  %fmt = getelementptr [4 x i8], [4 x i8]* @percent_s, i32 0, i32 0
+  %str = getelementptr [13 x i8], [13 x i8]* @hello_world, i32 0, i32 0
+  call i32 (i8*, ...) @printf(i8* %fmt, i8* %str)
+; CHECK:  call i32 @puts(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @hello_world, i64 0, i64 0))
+  ret void
+}
+
+; CHECK: Function Attrs: nounwind nonlazybind
+; CHECK-NEXT: declare i32 @puts(i8* nocapture readonly)
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 7, !"RtLibUseGOT", i32 1}