https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127352
Bug ID: 127352
Summary: [16/17 Regression] ICE in gen_reg_rtx at -O3
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: shimizu2486 at gmail dot com
Target Milestone: ---
Live Reproducer: https://godbolt.org/z/EbWrxManP
Compiling the following C with -O3 on x86_64-pc-linux-gnu 17.0.0 (trunk)
produces ICE:
$ cat ice.c
static long long add64(long long a, int b) { return a; }
static unsigned _BitInt(13) mod13(unsigned _BitInt(13) a, unsigned _BitInt(13)
b) { return b == 0 ? 1 : a; }
static _BitInt(65) mod65(_BitInt(65) a, _BitInt(65) b) { return b == 0 ? a : b;
}
_BitInt(65) g0, g1, g2;
__int128 w;
_BitInt(7) b7;
_BitInt(47) f0(long long p0) {
return ~add64(~(_BitInt(65))p0, 0);
}
_BitInt(5) f1(void) {
unsigned n1 = w & 15;
for (unsigned i2 = 0; i2 < n1; i2++) {
switch ((_BitInt(13))g0) {
case 0: g1 = 0;
case 8: b7 = 0; break;
case 10: b7 = f0(n1);
}
if (0 >= g1) continue;
for (unsigned i4 = 0; i4 < 1; i4++)
g1 = (_BitInt(7))(0 >= w ? mod13(b7, g0) : 0);
b7 = g2 ? mod65(g1, i2) : 0;
}
return g1;
}
This is an ICE on valid code. Compies on -O0 and no UB within.
$ gcc -O3 -c ice.c
during RTL pass: split2
ice.c:24:1: internal compiler error: in gen_reg_rtx, at emit-rtl.cc:1192
0x8381e3 gen_reg_rtx(machine_mode)
../../gcc/emit-rtl.cc:1192
0x1c94117 split_double_mode(machine_mode, rtx_def**, int, rtx_def**, rtx_def**)
../../gcc/config/i386/i386-expand.cc:166
0x26bc6ab gen_split_290(rtx_insn*, rtx_def**)
../../gcc/config/i386/i386.md:13311
0x2aa97e7 split_insns(rtx_def*, rtx_insn*)
../../gcc/config/i386/i386.md:21891
0x11dbe9e try_split(rtx_def*, rtx_insn*, int)
../../gcc/emit-rtl.cc:3960
0x1637077 split_insn
../../gcc/recog.cc:3529
0x163e955 split_all_insns()
../../gcc/recog.cc:3636
14 compiles
15 compiles
16 ICE
17 (trunk) ICE
