On Tue, Nov 25, 2014 at 09:20:13AM +0100, Jakub Jelinek wrote:
> Actually, thinking about it more, at least according to
> commutative_operand_precedence the canonical order is
> what we used to return (i.e. (something - _G_O_T_) + (symbol_ref)
> or
> (something - _G_O_T_) + (const (symbol_ref +- const))
> So perhaps better fix is to follow find_base_value, which does something
> like:
> /* Guess which operand is the base address:
> If either operand is a symbol, then it is the base. If
> either operand is a CONST_INT, then the other is the base. */
> if (CONST_INT_P (src_1) || CONSTANT_P (src_0))
> return find_base_value (src_0);
> else if (CONST_INT_P (src_0) || CONSTANT_P (src_1))
> return find_base_value (src_1);
> and do something similar in find_base_term too. I.e. perhaps even with
> higher precedence over REG_P with REG_POINTER (or lower, in these cases
> it doesn't really matter, neither argument is REG_P), choose first
> operand that is CONSTANT_P and not CONST_INT_P.
Here it is. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2014-11-26 Jakub Jelinek <ja...@redhat.com>
PR lto/64025
* alias.c (find_base_term): Use std::swap. Prefer tmp2
if it is CONSTANT_P other than CONST_INT.
--- gcc/alias.c.jj 2014-11-21 10:17:17.000000000 +0100
+++ gcc/alias.c 2014-11-26 12:31:24.719485590 +0100
@@ -1756,11 +1756,11 @@ find_base_term (rtx x)
if (REG_P (tmp1) && REG_POINTER (tmp1))
;
else if (REG_P (tmp2) && REG_POINTER (tmp2))
- {
- rtx tem = tmp1;
- tmp1 = tmp2;
- tmp2 = tem;
- }
+ std::swap (tmp1, tmp2);
+ /* If second argument is constant which has base term, prefer it
+ over variable tmp1. See PR64025. */
+ else if (CONSTANT_P (tmp2) && !CONST_INT_P (tmp2))
+ std::swap (tmp1, tmp2);
/* Go ahead and find the base term for both operands. If either base
term is from a pointer or is a named object or a special address
Jakub
