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| author | Richard Kenner <kenner@gcc.gnu.org> | 1993-08-18 19:30:08 -0400 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1993-08-18 19:30:08 -0400 |
| commit | f0343c749001041ed2ac488058581cbcecda6ae0 (patch) | |
| tree | 14eafefc92a2bf02983c1fd12e7c410225609f5f | |
| parent | 0840fd91a3ecc27805284548c687bc365581d031 (diff) | |
| download | gcc-f0343c749001041ed2ac488058581cbcecda6ae0.zip gcc-f0343c749001041ed2ac488058581cbcecda6ae0.tar.gz gcc-f0343c749001041ed2ac488058581cbcecda6ae0.tar.bz2 | |
(try_combine): Don't split a PARALLEL of a SIGN_EXTEND and the object being...
(try_combine): Don't split a PARALLEL of a SIGN_EXTEND and the object
being sign extended if we have made assumptions about the form the
I2DEST.
From-SVN: r5184
| -rw-r--r-- | gcc/combine.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index af83df5..4a91a3f 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -1825,7 +1825,11 @@ try_combine (i3, i2, i1) we have a PARALLEL with both loads from the same memory location. We can split this into a load from memory followed by a register-register copy. This saves at least one insn, more if register allocation can - eliminate the copy. */ + eliminate the copy. + + We cannot do this if the destination of the second assignment is + a register that we have already assumed is zero-extended. Similarly + for a SUBREG of such a register. */ else if (i1 && insn_code_number < 0 && asm_noperands (newpat) < 0 && GET_CODE (newpat) == PARALLEL @@ -1839,6 +1843,21 @@ try_combine (i3, i2, i1) INSN_CUID (i2)) && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != ZERO_EXTRACT && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != STRICT_LOW_PART + && ! (temp = SET_DEST (XVECEXP (newpat, 0, 1)), + (GET_CODE (temp) == REG + && reg_nonzero_bits[REGNO (temp)] != 0 + && GET_MODE_BITSIZE (GET_MODE (temp)) < BITS_PER_WORD + && GET_MODE_BITSIZE (GET_MODE (temp)) < HOST_BITS_PER_INT + && (reg_nonzero_bits[REGNO (temp)] + != GET_MODE_MASK (word_mode)))) + && ! (GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) == SUBREG + && (temp = SUBREG_REG (SET_DEST (XVECEXP (newpat, 0, 1))), + (GET_CODE (temp) == REG + && reg_nonzero_bits[REGNO (temp)] != 0 + && GET_MODE_BITSIZE (GET_MODE (temp)) < BITS_PER_WORD + && GET_MODE_BITSIZE (GET_MODE (temp)) < HOST_BITS_PER_INT + && (reg_nonzero_bits[REGNO (temp)] + != GET_MODE_MASK (word_mode))))) && ! reg_overlap_mentioned_p (SET_DEST (XVECEXP (newpat, 0, 1)), SET_SRC (XVECEXP (newpat, 0, 1))) && ! find_reg_note (i3, REG_UNUSED, |