| Message ID | 20101206183809.GV29412@tyan-ft48-01.lab.bos.redhat.com |
|---|---|
| State | New |
| Headers | show |
On 12/06/10 11:38, Jakub Jelinek wrote: > Hi! > > The following testcase ICEs, because a BB has a tablejump followed > by BARRIER in its il.rtl->header, and during unrolling duplicate_insn_chain > doesn't (intentionally) duplicate the tablejump, but does duplicate > the BARRIER into a header of many bbs, which breaks out of cfglayout > pass. > > Fixed by not duplicating the corresponding BARRIER either. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > 2010-12-06 Jakub Jelinek<jakub@redhat.com> > > PR rtl-optimization/46777 > * cfglayout.c (duplicate_insn_chain): Avoid duplicating > also barrier after tablejump. > > * gcc.dg/pr46777.c: New test. OK. Jeff
On 12/06/2010 07:38 PM, Jakub Jelinek wrote: > Hi! > > The following testcase ICEs, because a BB has a tablejump followed > by BARRIER in its il.rtl->header, and during unrolling duplicate_insn_chain > doesn't (intentionally) duplicate the tablejump, but does duplicate > the BARRIER into a header of many bbs, which breaks out of cfglayout > pass. > > Fixed by not duplicating the corresponding BARRIER either. I'm even more convinced that dropping (and eventually outlawing) BARRIERs in cfglayout mode would be a good idea... Paolo
--- gcc/cfglayout.c.jj 2010-11-19 20:56:55.000000000 +0100 +++ gcc/cfglayout.c 2010-12-06 14:51:01.000000000 +0100 @@ -1177,7 +1177,20 @@ duplicate_insn_chain (rtx from, rtx to) moved far from original jump. */ if (GET_CODE (PATTERN (insn)) == ADDR_VEC || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC) - break; + { + /* Avoid copying following barrier as well if any + (and debug insns in between). */ + rtx next; + + for (next = NEXT_INSN (insn); + next != NEXT_INSN (to); + next = NEXT_INSN (next)) + if (!DEBUG_INSN_P (next)) + break; + if (next != NEXT_INSN (to) && BARRIER_P (next)) + insn = next; + break; + } copy = emit_copy_of_insn_after (insn, get_last_insn ()); maybe_copy_prologue_epilogue_insn (insn, copy); break; --- gcc/testsuite/gcc.dg/pr46777.c.jj 2010-12-06 15:12:33.000000000 +0100 +++ gcc/testsuite/gcc.dg/pr46777.c 2010-12-06 15:10:21.000000000 +0100 @@ -0,0 +1,49 @@ +/* PR rtl-optimization/46777 */ +/* { dg-do compile } */ +/* { dg-options "-fgcse -O -fno-tree-dominator-opts -funroll-loops" } */ + +struct S { char s[256]; }; + +static inline int +foo (int x, int y) +{ + switch (x) + { + case 1: + case 2: + return 3; + case 3: + case 4: + return 2; + case 5: + switch (y) + { + case 4: + return 1; + } + } + return 0; +} + +void +bar (struct S *x, int *y, int *z, int **w) +{ + switch (*y ? x->s[*y] : foo (y[1], y[0])) + { + case 3: + if (y + 2 == z) + for (;;) + { + y += 2; + switch (*y ? x->s[*y] : foo (y[1], y[0])) + { + case 6: + break; + default: + *w = y; + } + if (y == z) + break; + } + } +}