From 8662d0593438ecd498ab7591ad0d2810886eb6da Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Tue, 7 Apr 2020 00:27:10 +0200 Subject: [PATCH] cselib: Fix endless cselib loop on (plus:P (reg) (const_int 0)) getopt.c hangs the compiler on h8300-elf with -O2 -g, because the IL contains addition of constant 0, the first PLUS operand is determined to have the SP_DERIVED_VALUE_P and the new code in cselib recurses indefinitely on seeing SP_DERIVED_VALUE_P with locs of (plus:P SP_DERIVED_VALUE_P (const_int 0)). Fixed by making sure cselib_subst_to_values canonicalizes it, hashing already hashes it the same too. 2020-04-06 Jakub Jelinek * cselib.c (cselib_subst_to_values): For SP_DERIVED_VALUE_P + const0_rtx return the SP_DERIVED_VALUE_P. --- gcc/ChangeLog | 5 +++++ gcc/cselib.c | 18 +++++++++++------- 2 files changed, 16 insertions(+), 7 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 258e9dbc956..40707325765 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2020-04-06 Jakub Jelinek + + * cselib.c (cselib_subst_to_values): For SP_DERIVED_VALUE_P + + const0_rtx return the SP_DERIVED_VALUE_P. + 2020-04-06 Richard Sandiford PR rtl-optimization/92989 diff --git a/gcc/cselib.c b/gcc/cselib.c index 256bd785207..69c9ca5b211 100644 --- a/gcc/cselib.c +++ b/gcc/cselib.c @@ -2090,13 +2090,17 @@ cselib_subst_to_values (rtx x, machine_mode memmode) { rtx t = cselib_subst_to_values (XEXP (x, 0), memmode); if (GET_CODE (t) == VALUE) - for (struct elt_loc_list *l = CSELIB_VAL_PTR (t)->locs; - l; l = l->next) - if (GET_CODE (l->loc) == PLUS - && GET_CODE (XEXP (l->loc, 0)) == VALUE - && SP_DERIVED_VALUE_P (XEXP (l->loc, 0)) - && CONST_INT_P (XEXP (l->loc, 1))) - return plus_constant (Pmode, l->loc, INTVAL (XEXP (x, 1))); + { + if (SP_DERIVED_VALUE_P (t) && XEXP (x, 1) == const0_rtx) + return t; + for (struct elt_loc_list *l = CSELIB_VAL_PTR (t)->locs; + l; l = l->next) + if (GET_CODE (l->loc) == PLUS + && GET_CODE (XEXP (l->loc, 0)) == VALUE + && SP_DERIVED_VALUE_P (XEXP (l->loc, 0)) + && CONST_INT_P (XEXP (l->loc, 1))) + return plus_constant (Pmode, l->loc, INTVAL (XEXP (x, 1))); + } if (t != XEXP (x, 0)) { copy = shallow_copy_rtx (x); -- 2.30.2