Hi!
The following testcase ICEs. The generated split_insns starts
with recog_data.insn = NULL and then tries to put various operands into
recog_data.operand array and checks various splitter conditions.
The problem is that some atom related tuning splitters indirectly call
extract_insn_cached on the insn they are used in. This can change
recog_data.operand, but most likely it will just keep it as is, but
sets recog_data.insn to the current instruction. If that splitter doesn't
match, we continue trying some other split conditions and modify
recog_data.operand array again. If even that doesn't find any usable
splitter, we punt, but at that point recog_data.insn says that recog_data
is valid for that particular instruction, even when recog_data.operand array
can be anything.
The safest thing would be to copy whole recog_data to a temporary object
before doing the calls that can call extract_insn_cached and restore it
afterwards, but it would be also very costly, recog_data has 1280 bytes.
So, this patch just makes sure to clear recog_data.insn if it has changed
during the extract_insn_cached call, which means if we extract_insn_cached
later, we'll extract it properly, while if we call it say from some other
context than splitter conditions, the insn is already cached, we don't reset
the cache.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2020-02-07 Jakub Jelinek <ja...@redhat.com>
PR target/93611
* config/i386/i386.c (ix86_lea_outperforms): Make sure to clear
recog_data.insn if distance_non_agu_define changed it.
* gcc.target/i386/pr93611.c: New test.
--- gcc/config/i386/i386.c.jj 2020-01-28 08:45:56.781090684 +0100
+++ gcc/config/i386/i386.c 2020-02-06 16:29:35.548663197 +0100
@@ -14459,9 +14459,18 @@ ix86_lea_outperforms (rtx_insn *insn, un
return true;
}
+ rtx_insn *rinsn = recog_data.insn;
+
dist_define = distance_non_agu_define (regno1, regno2, insn);
dist_use = distance_agu_use (regno0, insn);
+ /* distance_non_agu_define can call extract_insn_cached. If this function
+ is called from define_split conditions, that can break insn splitting,
+ because split_insns works by clearing recog_data.insn and then modifying
+ recog_data.operand array and match the various split conditions. */
+ if (recog_data.insn != rinsn)
+ recog_data.insn = NULL;
+
if (dist_define < 0 || dist_define >= LEA_MAX_STALL)
{
/* If there is no non AGU operand definition, no AGU
--- gcc/testsuite/gcc.target/i386/pr93611.c.jj 2020-02-06 12:24:28.005976435
+0100
+++ gcc/testsuite/gcc.target/i386/pr93611.c 2020-02-06 12:24:17.685131826
+0100
@@ -0,0 +1,5 @@
+/* PR target/93611 */
+/* { dg-do compile } */
+/* { dg-options "-fira-algorithm=priority -O3 -mtune=bonnell" } */
+
+#include "../../gcc.dg/vect/pr58508.c"
Jakub
