ahatanak added a comment.
> After going a bit through the log, I think that there is no reason for clang
> to not detect it, probably the check was just forgotten.
>
> This patch is the check.
Which part of your patch (in SemaStmtAsm.cpp) is supposed to catch that? I
applied this patch and rebuilt clang, but it still doesn't error out when it
compiles the function in my example (foo1).
> "r" constraint means (taken from the spec:) A register operand is allowed
> provided that it is in a general register.
> ("%rcx") means - use the register rcx.
Isn't a) equivalent to b)?
a)
__asm__ __volatile__ ("asm1 %0, %1": "=a" (c) : "r" ("%ebx") : "cc", "ebx"); //
do "b" and "%ebx" overlap?
b)
const char *s = "%ebx";
__asm__ __volatile__ ("asm1 %0, %1": "=a" (c) : "r" (s) : "cc", "ebx");
gcc and clang generate the same code for these two statements. I believe
constraint "r" means clang can use any general purpose registers for the
operand.
http://reviews.llvm.org/D15075
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