From 3d985316b89f2551a8fb39687bf4972b372ffdd7 Mon Sep 17 00:00:00 2001 From: Segher Boessenkool Date: Wed, 29 Nov 2017 23:51:16 +0100 Subject: [PATCH] combine: Print to dump if some insn cannot be combined into i3 Eventually we should print the reason that any combination fails. This is a good start (these happen often). * combine.c (try_combine): Print a message to dump file whenever I0, I1, or I2 cannot be combined into I3. From-SVN: r255261 --- gcc/ChangeLog | 5 +++++ gcc/combine.c | 24 ++++++++++++++++++------ 2 files changed, 23 insertions(+), 6 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index c13f67e76a6..d1838f19d6e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2017-11-29 Segher Boessenkool + + * combine.c (try_combine): Print a message to dump file whenever + I0, I1, or I2 cannot be combined into I3. + 2017-11-29 Segher Boessenkool PR rtl-optimization/83156 diff --git a/gcc/combine.c b/gcc/combine.c index cfe24f42633..863abd7a282 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -3035,13 +3035,25 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, SUBST (PATTERN (i2), XVECEXP (PATTERN (i2), 0, 1)); } - /* Verify that I2 and I1 are valid for combining. */ - if (! can_combine_p (i2, i3, i0, i1, NULL, NULL, &i2dest, &i2src) - || (i1 && ! can_combine_p (i1, i3, i0, NULL, i2, NULL, - &i1dest, &i1src)) - || (i0 && ! can_combine_p (i0, i3, NULL, NULL, i1, i2, - &i0dest, &i0src))) + /* Verify that I2 and maybe I1 and I0 can be combined into I3. */ + if (!can_combine_p (i2, i3, i0, i1, NULL, NULL, &i2dest, &i2src)) { + if (dump_file) + fprintf (dump_file, "Can't combine i2 into i3\n"); + undo_all (); + return 0; + } + if (i1 && !can_combine_p (i1, i3, i0, NULL, i2, NULL, &i1dest, &i1src)) + { + if (dump_file) + fprintf (dump_file, "Can't combine i1 into i3\n"); + undo_all (); + return 0; + } + if (i0 && !can_combine_p (i0, i3, NULL, NULL, i1, i2, &i0dest, &i0src)) + { + if (dump_file) + fprintf (dump_file, "Can't combine i0 into i3\n"); undo_all (); return 0; } -- 2.30.2