From 79d123c1c7478ff538d15e545c9f1164a9bb756c Mon Sep 17 00:00:00 2001 From: amodra Date: Fri, 1 Jul 2016 11:15:17 +0000 Subject: strcpy arg optimised out For functions that return an argument unchanged, like strcat, find_call_crossed_cheap_reg attempts to find an assignment between a pseudo reg and the arg reg before the call, so that uses of the pseudo after the call can instead use the return value. The exit condition on the loop looking at previous insns was wrong. Uses of the arg reg don't matter. What matters is the insn setting the arg reg as any assignment involving the arg reg prior to that insn is likely a completely unrelated use of the hard reg. PR rtl-optimization/71709 * ira-lives.c (find_call_crossed_cheap_reg): Exit loop on arg reg being set, not referenced. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@237909 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ChangeLog | 6 ++++++ gcc/ira-lives.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) (limited to 'gcc') diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 685847bf043..6551c0ec31c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2016-07-01 Alan Modra + + PR rtl-optimization/71709 + * ira-lives.c (find_call_crossed_cheap_reg): Exit loop on arg reg + being set, not referenced. + 2016-07-01 Yuri Rumyantsev PR tree-optimization/70729 diff --git a/gcc/ira-lives.c b/gcc/ira-lives.c index 6950ffb17b3..6b7ee81bea1 100644 --- a/gcc/ira-lives.c +++ b/gcc/ira-lives.c @@ -1014,7 +1014,7 @@ find_call_crossed_cheap_reg (rtx_insn *insn) break; } - if (reg_overlap_mentioned_p (reg, PATTERN (prev))) + if (reg_set_p (reg, prev)) break; } prev = PREV_INSN (prev); -- cgit v1.2.1