move an optimization for memcmp out of simplifylibcalls and into

SDISel.  This optimization was causing simplifylibcalls to 
introduce type-unsafe nastiness.  This is the first step, I'll be 
expanding the memcmp optimizations shortly, covering things that
we really really wouldn't want simplifylibcalls to do.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92098 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 76 insertions, 0 deletions

diff --git a/test/CodeGen/X86/memcmp.ll b/test/CodeGen/X86/memcmp.ll
new file mode 100644
index 0000000..f6086c4
--- /dev/null
+++ b/test/CodeGen/X86/memcmp.ll
@@ -0,0 +1,76 @@
+; RUN: llc %s -o - -march=x86-64 | FileCheck %s
+
+; This tests codegen time inlining/optimization of memcmp
+; rdar://6480398
+
+@.str = private constant [6 x i8] c"fooxx\00", align 1 ; <[6 x i8]*> [#uses=1]
+
+declare i32 @memcmp(...)
+
+define void @memcmp2(i8* %X, i8* %Y, i32* nocapture %P) nounwind {
+entry:
+  %0 = tail call i32 (...)* @memcmp(i8* %X, i8* %Y, i32 2) nounwind ; <i32> [#uses=1]
+  %1 = icmp eq i32 %0, 0                          ; <i1> [#uses=1]
+  br i1 %1, label %return, label %bb
+
+bb:                                               ; preds = %entry
+  store i32 4, i32* %P, align 4
+  ret void
+
+return:                                           ; preds = %entry
+  ret void
+; CHECK: memcmp2:
+; CHECK: movw    (%rsi), %ax
+; CHECK: cmpw    %ax, (%rdi)
+}
+
+define void @memcmp2a(i8* %X, i32* nocapture %P) nounwind {
+entry:
+  %0 = tail call i32 (...)* @memcmp(i8* %X, i8* getelementptr inbounds ([6 x i8]* @.str, i32 0, i32 1), i32 2) nounwind ; <i32> [#uses=1]
+  %1 = icmp eq i32 %0, 0                          ; <i1> [#uses=1]
+  br i1 %1, label %return, label %bb
+
+bb:                                               ; preds = %entry
+  store i32 4, i32* %P, align 4
+  ret void
+
+return:                                           ; preds = %entry
+  ret void
+; CHECK: memcmp2a:
+; CHECK: cmpw    $28527, (%rdi)
+}
+
+
+define void @memcmp4(i8* %X, i8* %Y, i32* nocapture %P) nounwind {
+entry:
+  %0 = tail call i32 (...)* @memcmp(i8* %X, i8* %Y, i32 4) nounwind ; <i32> [#uses=1]
+  %1 = icmp eq i32 %0, 0                          ; <i1> [#uses=1]
+  br i1 %1, label %return, label %bb
+
+bb:                                               ; preds = %entry
+  store i32 4, i32* %P, align 4
+  ret void
+
+return:                                           ; preds = %entry
+  ret void
+; CHECK: memcmp4:
+; CHECK: movl    (%rsi), %eax
+; CHECK: cmpl    %eax, (%rdi)
+}
+
+define void @memcmp4a(i8* %X, i32* nocapture %P) nounwind {
+entry:
+  %0 = tail call i32 (...)* @memcmp(i8* %X, i8* getelementptr inbounds ([6 x i8]* @.str, i32 0, i32 1), i32 4) nounwind ; <i32> [#uses=1]
+  %1 = icmp eq i32 %0, 0                          ; <i1> [#uses=1]
+  br i1 %1, label %return, label %bb
+
+bb:                                               ; preds = %entry
+  store i32 4, i32* %P, align 4
+  ret void
+
+return:                                           ; preds = %entry
+  ret void
+; CHECK: memcmp4a:
+; CHECK: cmpl $2021158767, (%rdi)
+}
+