diff options
| author | Richard Sandiford <rsandifo@redhat.com> | 2005-04-17 07:43:24 +0000 |
|---|---|---|
| committer | Richard Sandiford <rsandifo@gcc.gnu.org> | 2005-04-17 07:43:24 +0000 |
| commit | edb5d39c2d05072f003c13bfc9e23bd1e75b387e (patch) | |
| tree | 861812ca61ad47e557821dc2359ac5f01bf2cbf0 | |
| parent | 7ff2966ed88fff259fb2bb71f812c84d41fef130 (diff) | |
| download | gcc-edb5d39c2d05072f003c13bfc9e23bd1e75b387e.tar.gz | |
combine.c (combine_simplify_rtx): Remove a transformation that relies on an invalid assumption about rtl...
* combine.c (combine_simplify_rtx): Remove a transformation that
relies on an invalid assumption about rtl sign-extension semantics.
From-SVN: r98264
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/combine.c | 41 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 4 |
3 files changed, 9 insertions, 41 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ae1333eb6a5..c8ae193fbe8 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2005-04-17 Richard Sandiford <rsandifo@redhat.com> + + * combine.c (combine_simplify_rtx): Remove a transformation that + relies on an invalid assumption about rtl sign-extension semantics. + 2005-04-17 Richard Henderson <rth@redhat.com> PR target/20375 diff --git a/gcc/combine.c b/gcc/combine.c index 85dcfbf456c..58c82a674a2 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -3740,47 +3740,6 @@ combine_simplify_rtx (rtx x, enum machine_mode op0_mode, int in_dest) SUBST (XEXP (x, 1), temp); } - /* If this is a PLUS, MINUS, or MULT, and the first operand is the - sign extension of a PLUS with a constant, reverse the order of the sign - extension and the addition. Note that this not the same as the original - code, but overflow is undefined for signed values. Also note that the - PLUS will have been partially moved "inside" the sign-extension, so that - the first operand of X will really look like: - (ashiftrt (plus (ashift A C4) C5) C4). - We convert this to - (plus (ashiftrt (ashift A C4) C2) C4) - and replace the first operand of X with that expression. Later parts - of this function may simplify the expression further. - - For example, if we start with (mult (sign_extend (plus A C1)) C2), - we swap the SIGN_EXTEND and PLUS. Later code will apply the - distributive law to produce (plus (mult (sign_extend X) C1) C3). - - We do this to simplify address expressions. */ - - if ((code == PLUS || code == MINUS || code == MULT) - && GET_CODE (XEXP (x, 0)) == ASHIFTRT - && GET_CODE (XEXP (XEXP (x, 0), 0)) == PLUS - && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == ASHIFT - && GET_CODE (XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 1)) == CONST_INT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 1) == XEXP (XEXP (x, 0), 1) - && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 1)) == CONST_INT - && (temp = simplify_binary_operation (ASHIFTRT, mode, - XEXP (XEXP (XEXP (x, 0), 0), 1), - XEXP (XEXP (x, 0), 1))) != 0) - { - rtx new - = simplify_shift_const (NULL_RTX, ASHIFT, mode, - XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 0), - INTVAL (XEXP (XEXP (x, 0), 1))); - - new = simplify_shift_const (NULL_RTX, ASHIFTRT, mode, new, - INTVAL (XEXP (XEXP (x, 0), 1))); - - SUBST (XEXP (x, 0), simplify_gen_binary (PLUS, mode, new, temp)); - } - /* If this is a simple operation applied to an IF_THEN_ELSE, try applying it to the arms of the IF_THEN_ELSE. This often simplifies things. Check for cases where both arms are testing the same diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index fb434e68942..eb93537df20 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2005-04-17 Richard Sandiford <rsandifo@redhat.com> + + * gcc.c-torture/execute/20050410-1.c: New test. + 2005-04-17 Alexandre Oliva <aoliva@redhat.com> PR middle-end/20739 |