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So my tester started showing even more regressions on the sh3/sh4 runs recently (beyond the one recently reported in BZ triggered by some DCE related changes). Bisection kept showing inconsistent results. I was starting to think memory management error, but valgrind didn't flag anything. After a bit of head-banging I was able to track it down to predicate tests called from the SH specific combiner passes. And once I started getting inside the actual code for the predicate function it became pretty obvious. The predicate routines are supposed to return a bool, fine and they dutifully set the low bit in %eax properly. The *caller* was looking at the full register. Uh-oh. Naturally we became dependent on what happened to be in the upper 31 bits of a register. That's why the bug would come and go so willy-nilly. This was ultimately chased down to an incorrect prototype in sh_treg_combine.cc for predicate functions defined via define_predicate. Removing the bogus prototypes and instead including the generated tm-preds.h fixes this problem. I also checked the other ports for similar problems (specifically looking for a extern int.*_operand, then for each of the hits looking to see if the predicate was defined via define_predicate). No other ports had similar braindamage. This fixes the most recent regressions in my tester for sh3/sh3eb and I strongly suspect sh4. It does not fix 107704, but I think Richi and I both agree that's a visitation order issue and we were just getting lucky before. gcc/ * config/sh/sh_treg_combine.cc: Include tm-preds.h. (t_reg_operand): Remove bogus prototype. (negt_reg_operand): Likewise.
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