From 55dcc361e67fb135be96f5e80e93ee98304b3c1e Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Fri, 1 Jul 2016 20:45:17 +0930 Subject: [PATCH] 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. From-SVN: r237909 --- gcc/ChangeLog | 6 ++++++ gcc/ira-lives.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) 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); -- 2.30.2