diff options
Diffstat (limited to 'gcc/compare-elim.c')
| -rw-r--r-- | gcc/compare-elim.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/gcc/compare-elim.c b/gcc/compare-elim.c index 50bbaa8..8afbe76 100644 --- a/gcc/compare-elim.c +++ b/gcc/compare-elim.c @@ -734,7 +734,7 @@ try_merge_compare (struct comparison *cmp) static bool try_eliminate_compare (struct comparison *cmp) { - rtx flags, in_a, in_b, cmp_src; + rtx flags, in_a, in_b, cmp_a, cmp_b; if (try_merge_compare (cmp)) return true; @@ -786,7 +786,7 @@ try_eliminate_compare (struct comparison *cmp) rtx x = XVECEXP (PATTERN (insn), 0, 0); if (rtx_equal_p (SET_DEST (x), in_a)) - cmp_src = SET_SRC (x); + cmp_a = SET_SRC (x); /* Also check operations with implicit extensions, e.g.: [(set (reg:DI) @@ -800,7 +800,7 @@ try_eliminate_compare (struct comparison *cmp) && (GET_CODE (SET_SRC (x)) == ZERO_EXTEND || GET_CODE (SET_SRC (x)) == SIGN_EXTEND) && GET_MODE (XEXP (SET_SRC (x), 0)) == GET_MODE (in_a)) - cmp_src = XEXP (SET_SRC (x), 0); + cmp_a = XEXP (SET_SRC (x), 0); /* Also check fully redundant comparisons, e.g.: [(set (reg:SI) @@ -811,7 +811,7 @@ try_eliminate_compare (struct comparison *cmp) && GET_CODE (SET_SRC (x)) == MINUS && rtx_equal_p (XEXP (SET_SRC (x), 0), in_a) && rtx_equal_p (XEXP (SET_SRC (x), 1), in_b)) - cmp_src = in_a; + cmp_a = in_a; else return false; @@ -819,17 +819,26 @@ try_eliminate_compare (struct comparison *cmp) /* If the source uses addressing modes with side effects, we can't do the merge because we'd end up with a PARALLEL that has two instances of that side effect in it. */ - if (side_effects_p (cmp_src)) + if (side_effects_p (cmp_a)) + return false; + + if (in_a == in_b) + cmp_b = cmp_a; + else if (rtx_equal_p (SET_DEST (x), in_b)) + cmp_b = SET_SRC (x); + else + cmp_b = in_b; + if (side_effects_p (cmp_b)) return false; /* Determine if we ought to use a different CC_MODE here. */ - flags = maybe_select_cc_mode (cmp, cmp_src, in_b); + flags = maybe_select_cc_mode (cmp, cmp_a, cmp_b); if (flags == NULL) flags = gen_rtx_REG (cmp->orig_mode, targetm.flags_regnum); /* Generate a new comparison for installation in the setter. */ - rtx y = copy_rtx (cmp_src); - y = gen_rtx_COMPARE (GET_MODE (flags), y, in_b); + rtx y = copy_rtx (cmp_a); + y = gen_rtx_COMPARE (GET_MODE (flags), y, copy_rtx (cmp_b)); y = gen_rtx_SET (flags, y); /* Canonicalize instruction to: |