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| author | Pat Haugen <pthaugen@us.ibm.com> | 2004-10-18 18:46:06 +0000 |
|---|---|---|
| committer | David Edelsohn <dje@gcc.gnu.org> | 2004-10-18 14:46:06 -0400 |
| commit | b757b9f8b210b691f72fe418db8c0767bda54cb7 (patch) | |
| tree | 4c36b35633d0f938381ebc4187f4b32439f4546d /gcc/combine.c | |
| parent | 1a1804c27017289c540fd8b193209a8598af858a (diff) | |
| download | gcc-b757b9f8b210b691f72fe418db8c0767bda54cb7.zip gcc-b757b9f8b210b691f72fe418db8c0767bda54cb7.tar.gz gcc-b757b9f8b210b691f72fe418db8c0767bda54cb7.tar.bz2 | |
simplify-rtx.c (mode_signbit_p): Externalize function...
2004-10-18 Pat Haugen <pthaugen@us.ibm.com>
* simplify-rtx.c (mode_signbit_p): Externalize function...
* rtl.h (mode_signbit_p): ... to here.
* combine.c (simplify_shift_const): Recognize PLUS signbit as
canonical form of XOR signbit and move to outer op.
From-SVN: r89235
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 559ee15..98efe3e 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -9022,6 +9022,26 @@ simplify_shift_const (rtx x, enum rtx_code code, varop = XEXP (varop, 0); continue; } + + /* Check for 'PLUS signbit', which is the canonical form of 'XOR + signbit', and attempt to change the PLUS to an XOR and move it to + the outer operation as is done above in the AND/IOR/XOR case + leg for shift(logical). See details in logical handling above + for reasoning in doing so. */ + if (code == LSHIFTRT + && GET_CODE (XEXP (varop, 1)) == CONST_INT + && mode_signbit_p (result_mode, XEXP (varop, 1)) + && (new = simplify_binary_operation (code, result_mode, + XEXP (varop, 1), + GEN_INT (count))) != 0 + && GET_CODE (new) == CONST_INT + && merge_outer_ops (&outer_op, &outer_const, XOR, + INTVAL (new), result_mode, &complement_p)) + { + varop = XEXP (varop, 0); + continue; + } + break; case MINUS: |