| Message ID | CAMe9rOq45FqsAy_QFSyUsBVj0SYxjqcLeNm_R8-PMtykuefJeQ@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
"H.J. Lu" <hjl.tools@gmail.com> writes: >>> LRA has >>> >>> if (REG_P (reg) && (ep = get_elimination (reg)) != NULL) >>> { >>> rtx to_rtx = replace_p ? ep->to_rtx : ep->from_rtx; >>> >>> if (! replace_p) >>> { >>> offset += (ep->offset - ep->previous_offset); >>> offset = trunc_int_for_mode (offset, GET_MODE (plus_cst_src)); >>> } >>> >>> if (GET_CODE (XEXP (plus_cst_src, 0)) == SUBREG) >>> to_rtx = gen_lowpart (GET_MODE (XEXP (plus_cst_src, 0)), to_rtx); >>> >>> Reload has >>> >>> rtx to_rtx = ep->to_rtx; >>> offset += ep->offset; >>> offset = trunc_int_for_mode (offset, GET_MODE (plus_cst_src)); >>> >>> if (GET_CODE (XEXP (plus_cst_src, 0)) == SUBREG) >>> to_rtx = gen_lowpart (GET_MODE (XEXP (plus_cst_src, 0)), >>> to_rtx); >>> >>> (gdb) call debug_rtx (ep->to_rtx) >>> (reg/f:DI 7 sp) >>> (gdb) call debug_rtx (ep->from_rtx) >>> (reg/f:DI 16 argp) >>> (gdb) >>> >>> gen_lowpart returns (reg/f:DI 7 sp) for reload and (reg:SI 16 argp) >>> for LRA. They are caused by >>> >>> if (FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM >>> /* We should convert arg register in LRA after the elimination >>> if it is possible. */ >>> && xregno == ARG_POINTER_REGNUM >>> && ! lra_in_progress) >>> return -1; >>> >>> It doesn't work in this case. >>> >> >> This testcase shows that LRA can't convert arg register after >> the elimination. >> > Here is a patch to remove ra_in_progress check for > ARG_POINTER_REGNUM. Tested on Linux.x86-64. > OK to install? Thanks HJ. This looks good to me. As well as your testcase, I think it would be dangerous to reduce this kind of subreg during non-final elimination in cases where the argument pointer occupies more than one hard register (like avr IIRC). We could end up with something like ARG_POINTER_REGNUM+1, which wouldn't show up as an elimination register during the rest of LRA. It's important that we do get rid of the subreg during the final elimination stage, but I think alter_subreg already handles that case. Since this code is outside the LRA files: patch is OK if Vlad agrees. Richard
On 10/30/2012 06:34 AM, Richard Sandiford wrote: > "H.J. Lu" <hjl.tools@gmail.com> writes: >>>> LRA has >>>> >>>> if (REG_P (reg) && (ep = get_elimination (reg)) != NULL) >>>> { >>>> rtx to_rtx = replace_p ? ep->to_rtx : ep->from_rtx; >>>> >>>> if (! replace_p) >>>> { >>>> offset += (ep->offset - ep->previous_offset); >>>> offset = trunc_int_for_mode (offset, GET_MODE (plus_cst_src)); >>>> } >>>> >>>> if (GET_CODE (XEXP (plus_cst_src, 0)) == SUBREG) >>>> to_rtx = gen_lowpart (GET_MODE (XEXP (plus_cst_src, 0)), to_rtx); >>>> >>>> Reload has >>>> >>>> rtx to_rtx = ep->to_rtx; >>>> offset += ep->offset; >>>> offset = trunc_int_for_mode (offset, GET_MODE (plus_cst_src)); >>>> >>>> if (GET_CODE (XEXP (plus_cst_src, 0)) == SUBREG) >>>> to_rtx = gen_lowpart (GET_MODE (XEXP (plus_cst_src, 0)), >>>> to_rtx); >>>> >>>> (gdb) call debug_rtx (ep->to_rtx) >>>> (reg/f:DI 7 sp) >>>> (gdb) call debug_rtx (ep->from_rtx) >>>> (reg/f:DI 16 argp) >>>> (gdb) >>>> >>>> gen_lowpart returns (reg/f:DI 7 sp) for reload and (reg:SI 16 argp) >>>> for LRA. They are caused by >>>> >>>> if (FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM >>>> /* We should convert arg register in LRA after the elimination >>>> if it is possible. */ >>>> && xregno == ARG_POINTER_REGNUM >>>> && ! lra_in_progress) >>>> return -1; >>>> >>>> It doesn't work in this case. >>>> >>> This testcase shows that LRA can't convert arg register after >>> the elimination. >>> >> Here is a patch to remove ra_in_progress check for >> ARG_POINTER_REGNUM. Tested on Linux.x86-64. >> OK to install? > Thanks HJ. This looks good to me. As well as your testcase, I think > it would be dangerous to reduce this kind of subreg during non-final > elimination in cases where the argument pointer occupies more than one > hard register (like avr IIRC). We could end up with something like > ARG_POINTER_REGNUM+1, which wouldn't show up as an elimination register > during the rest of LRA. > > It's important that we do get rid of the subreg during the final > elimination stage, but I think alter_subreg already handles that case. > > Since this code is outside the LRA files: patch is OK if Vlad agrees. > I added this code for a reason probably to solve some target problems. So I am not sure but let us try. It is ok for me to commit the patch if there are no regressions on x86/x86-64.
diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c index 43d4cb8..c1a7580 100644 --- a/gcc/rtlanal.c +++ b/gcc/rtlanal.c @@ -3494,10 +3494,7 @@ simplify_subreg_regno (unsigned int xregno, enum machine_mode xmode, return -1; if (FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM - /* We should convert arg register in LRA after the elimination - if it is possible. */ - && xregno == ARG_POINTER_REGNUM - && ! lra_in_progress) + && xregno == ARG_POINTER_REGNUM) return -1; if (xregno == STACK_POINTER_REGNUM diff --git a/gcc/testsuite/gcc.target/i386/pr55093.c b/gcc/testsuite/gcc.target/i386/pr55093.c new file mode 100644 index 0000000..76b4042 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr55093.c @@ -0,0 +1,80 @@ +/* { dg-do compile { target { ! { ia32 } } } } */ +/* { dg-options "-O2 -mx32 -maddress-mode=long" } */ + +typedef union tree_node *tree; +typedef const union tree_node *const_tree; +typedef struct { + unsigned long long low; + long long high; +} double_int; +struct real_value { +}; +struct real_format { + int has_signed_zero; +}; +extern const struct real_format * real_format_for_mode[]; +extern int real_isnegzero (const struct real_value *); +enum tree_code { REAL_CST, SSA_NAME }; +struct tree_base { + enum tree_code code : 16; + union { + unsigned int version; + } + u; +}; +extern void tree_check_failed (const_tree, const char *, int, const char *, ...) __attribute__ ((__noreturn__)); +union tree_node { + struct tree_base base; +}; +inline tree tree_check (tree __t, const char *__f, int __l, const char *__g, enum tree_code __c) { + if (((enum tree_code) (__t)->base.code) != __c) + tree_check_failed (__t, __f, __l, __g, __c, 0); + return __t; +} +struct prop_value_d { + int lattice_val; + tree value; + double_int mask; +}; +typedef struct prop_value_d prop_value_t; +static prop_value_t *const_val; +static void canonicalize_float_value (prop_value_t *); +typedef void (*ssa_prop_visit_stmt_fn) (prop_value_t); +typedef void (*ssa_prop_visit_phi_fn) (void); +typedef void (*ssa_prop_fold_stmt_fn) (void *gsi); +typedef void (*ssa_prop_get_value_fn) ( prop_value_t *val); +void ssa_propagate (ssa_prop_visit_stmt_fn, ssa_prop_visit_phi_fn); +int substitute_and_fold (ssa_prop_get_value_fn, ssa_prop_fold_stmt_fn); +void ccp_fold_stmt (void *); +static void get_constant_value (prop_value_t *val) { + canonicalize_float_value (val); +} +static void canonicalize_float_value (prop_value_t *val) { + int mode; + struct real_value d; + if (val->lattice_val != 1 + || ((enum tree_code) (val->value)->base.code) != REAL_CST) + return; + mode = val->lattice_val; + if (real_format_for_mode[mode]->has_signed_zero && real_isnegzero (&d)) + ccp_fold_stmt (0); +} +static void set_lattice_value (tree var, prop_value_t new_val) { + prop_value_t *old_val = &const_val[(tree_check ((var), "", + 0, "", + (SSA_NAME)))->base.u.version]; + canonicalize_float_value (&new_val); + canonicalize_float_value (old_val); +} +static void ccp_visit_phi_node (void) { + prop_value_t new_val; + set_lattice_value (0, new_val); +} +static void ccp_visit_stmt (prop_value_t v) { + set_lattice_value (0, v); +} +unsigned int do_ssa_ccp (void) { + ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); + substitute_and_fold (get_constant_value, ccp_fold_stmt);