On 2016.10.18 at 05:13 +0200, Markus Trippelsdorf wrote: > On 2016.10.17 at 17:23 -0500, Bill Schmidt wrote: > > Hi, > > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77916 identifies a situation > > where SLSR will ICE when exposed to a cast from integer to pointer. This > > is because we try to convert a PLUS_EXPR with an addend of -1 * S into a > > MINUS_EXPR with a subtrahend of S, but the base operand is unexpectedly > > of pointer type. This patch recognizes when pointer arithmetic is taking > > place and ensures that we use a POINTER_PLUS_EXPR at all such times. In > > the case of the PR, this occurs in the logic where the stride S is a known > > constant value, but the same problem could occur when it is an SSA_NAME > > without known value. Both possibilities are handled here. > > > > Fixing the code to ensure that the unknown stride case always uses an > > initializer for a negative increment allows us to remove the stopgap fix > > added for PR77937 as well. > > > > Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no > > regressions, committed. > > Perhaps you should consider building ffmpeg with -O3 -march=amdfam10 on > X86_64 before committing these patches, because you broke it for the > third time in the last couple of days. > > markus@x4 ffmpeg % cat h264dsp.i > extern int fn2(int); > extern int fn3(int); > int a, b, c; > void fn1(long p1) { > char *d; > for (;; d += p1) { > d[0] = fn2(1 >> c >> 1); > fn2(c >> a); > d[1] = fn3(d[1]) >> 1; > d[6] = fn3(d[6] * b + 1) >> 1; > d[7] = fn3(d[7] * b + 1) >> 1; > d[8] = fn3(d[8] * b + 1) >> 1; > } > } > > markus@x4 ffmpeg % gcc -O3 -march=amdfam10 -c h264dsp.i > h264dsp.i: In function ‘fn1’: > h264dsp.i:4:6: internal compiler error: in replace_one_candidate, at > gimple-ssa-strength-reduction.c:3375 > void fn1(long p1) { > ^~~ > 0x12773a9 replace_one_candidate > ../../gcc/gcc/gimple-ssa-strength-reduction.c:3375 > 0x127af77 replace_profitable_candidates > ../../gcc/gcc/gimple-ssa-strength-reduction.c:3486 > 0x127aeeb replace_profitable_candidates > ../../gcc/gcc/gimple-ssa-strength-reduction.c:3495 > 0x127f3ee analyze_candidates_and_replace > ../../gcc/gcc/gimple-ssa-strength-reduction.c:3574 > 0x127f3ee execute > ../../gcc/gcc/gimple-ssa-strength-reduction.c:3648
Just figured out that this testcase is identical to: gcc/testsuite/gcc.dg/torture/pr77937-2.c So please run the testsuite on X86_64 in the future. -- Markus
