From d7ec518927f92d794dd1ecf59567b040ed6e29f6 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Mon, 24 Apr 2006 23:30:10 +0000
Subject: [PATCH] Add a new entry.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27963 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Target/X86/README.txt | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index 2ce31d2224d..4016e4ee7a2 100644
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -1075,3 +1075,35 @@ http://gcc.gnu.org/bugzilla/attachment.cgi?id=8701
There is also one case we do worse on PPC.
//===---------------------------------------------------------------------===//
+
+For this:
+
+#include <emmintrin.h>
+void test(__m128d *r, __m128d *A, double B) {
+ *r = _mm_loadl_pd(*A, &B);
+}
+
+We generates:
+
+ subl $12, %esp
+ movsd 24(%esp), %xmm0
+ movsd %xmm0, (%esp)
+ movl 20(%esp), %eax
+ movapd (%eax), %xmm0
+ movlpd (%esp), %xmm0
+ movl 16(%esp), %eax
+ movapd %xmm0, (%eax)
+ addl $12, %esp
+ ret
+
+icc generates:
+
+ movl 4(%esp), %edx #3.6
+ movl 8(%esp), %eax #3.6
+ movapd (%eax), %xmm0 #4.22
+ movlpd 12(%esp), %xmm0 #4.8
+ movapd %xmm0, (%edx) #4.3
+ ret #5.1
+
+So icc is smart enough to know that B is in memory so it doesn't load it and
+store it back to stack.