From f96ca79cf3b64b6174d14e1a747ec145b112ed97 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sat, 6 Dec 2008 22:49:05 +0000 Subject: [PATCH] add a note git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60632 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/README.txt | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index c02eca6410f..eb110fe60f6 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -1816,3 +1816,18 @@ like the following: A similar code sequence works for division. //===---------------------------------------------------------------------===// + +These should compile to the same code, but the later codegen's to useless +instructions on X86. This may be a trivial dag combine (GCC PR7061): + +struct s1 { unsigned char a, b; }; +unsigned long f1(struct s1 x) { + return x.a + x.b; +} +struct s2 { unsigned a: 8, b: 8; }; +unsigned long f2(struct s2 x) { + return x.a + x.b; +} + +//===---------------------------------------------------------------------===// + -- 2.34.1