Hi!
This ICEs because split2 splits a HImode rotate by 8 into an instruction
that isn't really valid (bswaphi_lowpart insn, which has preferred_for_size
enabled just the first alternative that uses +Q, while the splitter creates
insn with %r9) and the second alternative with +r should be disabled.
For some reason we don't ICE on that, but when -mmitigate-rop mach subpass
uses regrename framework and changes that %r9 register to yet another non-Q
register (%si) it isn't recognized because the second alternative is
disabled.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2018-01-04 Jakub Jelinek <ja...@redhat.com>
Uros Bizjak <ubiz...@gmail.com>
PR target/83554
* config/i386/i386.md (*<rotate_insn>hi3_1 splitter): Use
QIreg_operand instead of register_operand predicate.
* config/i386/i386.c (ix86_rop_should_change_byte_p,
set_rop_modrm_reg_bits, ix86_mitigate_rop): Use -mmitigate-rop in
comments instead of -fmitigate[-_]rop.
* gcc.target/i386/pr83554.c: New test.
--- gcc/config/i386/i386.md.jj 2018-01-04 12:37:23.609487117 +0100
+++ gcc/config/i386/i386.md 2018-01-04 14:23:09.436675176 +0100
@@ -11643,7 +11643,7 @@ (define_insn "*<rotate_insn>qi3_1_slp"
(set_attr "mode" "QI")])
(define_split
- [(set (match_operand:HI 0 "register_operand")
+ [(set (match_operand:HI 0 "QIreg_operand")
(any_rotate:HI (match_dup 0) (const_int 8)))
(clobber (reg:CC FLAGS_REG))]
"reload_completed
--- gcc/config/i386/i386.c.jj 2018-01-04 12:37:23.611487117 +0100
+++ gcc/config/i386/i386.c 2018-01-04 14:22:24.490657996 +0100
@@ -3089,7 +3089,7 @@ ix86_debug_options (void)
}
/* Return true if T is one of the bytes we should avoid with
- -fmitigate-rop. */
+ -mmitigate-rop. */
static bool
ix86_rop_should_change_byte_p (int t)
@@ -41175,7 +41175,7 @@ ix86_seh_fixup_eh_fallthru (void)
/* Given a register number BASE, the lowest of a group of registers, update
regsets IN and OUT with the registers that should be avoided in input
and output operands respectively when trying to avoid generating a modr/m
- byte for -fmitigate-rop. */
+ byte for -mmitigate-rop. */
static void
set_rop_modrm_reg_bits (int base, HARD_REG_SET &in, HARD_REG_SET &out)
@@ -41186,7 +41186,7 @@ set_rop_modrm_reg_bits (int base, HARD_R
SET_HARD_REG_BIT (in, base + 3);
}
-/* Called if -fmitigate_rop is in effect. Try to rewrite instructions so
+/* Called if -mmitigate-rop is in effect. Try to rewrite instructions so
that certain encodings of modr/m bytes do not occur. */
static void
ix86_mitigate_rop (void)
--- gcc/testsuite/gcc.target/i386/pr83554.c.jj 2018-01-04 14:22:24.491657997
+0100
+++ gcc/testsuite/gcc.target/i386/pr83554.c 2018-01-04 14:22:24.491657997
+0100
@@ -0,0 +1,15 @@
+/* PR target/83554 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-Os -mmitigate-rop" } */
+
+unsigned a;
+unsigned __int128
+foo (unsigned char c, unsigned short d, unsigned e, unsigned long f,
+ unsigned __int128 g, unsigned h, unsigned short i, unsigned long j)
+{
+ j /= (unsigned)-2;
+ h += h &= c == c;
+ h -= g;
+ i = i >> 8 | i << 8;
+ return c + d + e + f + g + h + i + j + a;
+}
Jakub
