Message ID | 20110707101935.GM2687@tyan-ft48-01.lab.bos.redhat.com |
---|---|
State | New |
Headers | show |
> So, here is a new patch which doesn't need two loops, just might go a > little bit backwards to unchain dead_debug_use for the reset insn. > > It still needs the change of the gcc_assert (reg) into if (reg == NULL) > return;, because the dead->used bitmap is with this sometimes a false > positive (saying that a regno is referenced even when it isn't). > But here it is IMHO better to occassionaly live with the false positives, > which just means we'll sometimes once walk the chain in dead_debug_reset > or dead_debug_insert_before before resetting it, than to recompute the > bitmap (we'd need a second loop for that, bitmap_clear (debug->used) and > populate it again). Fine with me for both points, but move some bits of these explanations to the code itself because this isn't obvious. For example see below. > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > 2011-07-07 Jakub Jelinek <jakub@redhat.com> > > PR debug/49522 > * df-problems.c (dead_debug_reset): Remove dead_debug_uses > referencing debug insns that have been reset. > (dead_debug_insert_before): Don't assert reg is non-NULL, > instead return immediately if it is NULL. > > * gcc.dg/debug/pr49522.c: New test. OK, thanks. > --- gcc/df-problems.c.jj 2011-07-07 02:32:45.928547053 +0200 > +++ gcc/df-problems.c 2011-07-07 09:57:34.846464573 +0200 > @@ -3096,6 +3096,7 @@ static void > dead_debug_reset (struct dead_debug *debug, unsigned int dregno) > { > struct dead_debug_use **tailp = &debug->head; > + struct dead_debug_use **insnp = &debug->head; > struct dead_debug_use *cur; > rtx insn; > > @@ -3113,9 +3114,21 @@ dead_debug_reset (struct dead_debug *deb > debug->to_rescan = BITMAP_ALLOC (NULL); > bitmap_set_bit (debug->to_rescan, INSN_UID (insn)); > XDELETE (cur); > + if (tailp != insnp && DF_REF_INSN ((*insnp)->use) == insn) > + tailp = insnp; /* If the current use isn't the first one attached to INSN, go back to this first use. We assume that the uses attached to an insn are adjacent. */ > + while ((cur = *tailp) && DF_REF_INSN (cur->use) == insn) > + { > + *tailp = cur->next; > + XDELETE (cur); > + } > + insnp = tailp; /* Then remove all the other uses attached to INSN. */ > } > else > - tailp = &(*tailp)->next; > + { > + if (DF_REF_INSN ((*insnp)->use) != DF_REF_INSN (cur->use)) > + insnp = tailp; > + tailp = &(*tailp)->next; > + } > } > } > > @@ -3174,7 +3187,8 @@ dead_debug_insert_before (struct dead_de > tailp = &(*tailp)->next; > } > > - gcc_assert (reg); > + if (reg == NULL) > + return; /* We may have dangling bits in debug->used for registers that were part of a multi-register use, one component of which has been reset. */
--- gcc/df-problems.c.jj 2011-07-07 02:32:45.928547053 +0200 +++ gcc/df-problems.c 2011-07-07 09:57:34.846464573 +0200 @@ -3096,6 +3096,7 @@ static void dead_debug_reset (struct dead_debug *debug, unsigned int dregno) { struct dead_debug_use **tailp = &debug->head; + struct dead_debug_use **insnp = &debug->head; struct dead_debug_use *cur; rtx insn; @@ -3113,9 +3114,21 @@ dead_debug_reset (struct dead_debug *deb debug->to_rescan = BITMAP_ALLOC (NULL); bitmap_set_bit (debug->to_rescan, INSN_UID (insn)); XDELETE (cur); + if (tailp != insnp && DF_REF_INSN ((*insnp)->use) == insn) + tailp = insnp; + while ((cur = *tailp) && DF_REF_INSN (cur->use) == insn) + { + *tailp = cur->next; + XDELETE (cur); + } + insnp = tailp; } else - tailp = &(*tailp)->next; + { + if (DF_REF_INSN ((*insnp)->use) != DF_REF_INSN (cur->use)) + insnp = tailp; + tailp = &(*tailp)->next; + } } } @@ -3174,7 +3187,8 @@ dead_debug_insert_before (struct dead_de tailp = &(*tailp)->next; } - gcc_assert (reg); + if (reg == NULL) + return; /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */ dval = make_debug_expr_from_rtl (reg); --- gcc/testsuite/gcc.dg/debug/pr49522.c.jj 2011-07-04 10:54:23.000000000 +0200 +++ gcc/testsuite/gcc.dg/debug/pr49522.c 2011-07-04 10:54:02.000000000 +0200 @@ -0,0 +1,41 @@ +/* PR debug/49522 */ +/* { dg-do compile } */ +/* { dg-options "-fcompare-debug" } */ + +int val1 = 0L; +volatile int val2 = 7L; +long long val3; +int *ptr = &val1; + +static int +func1 () +{ + return 0; +} + +static short int +func2 (short int a, unsigned int b) +{ + return !b ? a : a >> b; +} + +static unsigned long long +func3 (unsigned long long a, unsigned long long b) +{ + return !b ? a : a % b; +} + +void +func4 (unsigned short arg1, int arg2) +{ + for (arg2 = 0; arg2 < 2; arg2++) + { + *ptr = func3 (func3 (10, func2 (val3, val2)), val3); + for (arg1 = -14; arg1 > 14; arg1 = func1 ()) + { + *ptr = -1; + if (foo ()) + ; + } + } +}