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combine patch
- To: egcs-patches at cygnus dot com
- Subject: combine patch
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Mon, 05 Oct 1998 10:05:48 -0600
- Reply-To: law at cygnus dot com
I've installed this to fix a code generation error for our mips64 ports. We
incorrectly eliminated a TRUNCATE operation.
* combine.c (simplify_rtx): Do not replace TRUNCATE with a SUBREG if
truncation is not a no-op.
Index: combine.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gcc/combine.c,v
retrieving revision 1.185
diff -c -3 -p -r1.185 combine.c
*** combine.c 1998/09/16 05:48:22 1.185
--- combine.c 1998/10/05 16:02:53
*************** simplify_rtx (x, op0_mode, last, in_dest
*** 3891,3899 ****
return SUBREG_REG (XEXP (x, 0));
/* If we know that the value is already truncated, we can
! replace the TRUNCATE with a SUBREG. */
! if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0)))
! >= GET_MODE_BITSIZE (mode) + 1)
return gen_lowpart_for_combine (mode, XEXP (x, 0));
/* A truncate of a comparison can be replaced with a subreg if
--- 3891,3902 ----
return SUBREG_REG (XEXP (x, 0));
/* If we know that the value is already truncated, we can
! replace the TRUNCATE with a SUBREG if TRULY_NOOP_TRUNCATION is
! nonzero for the corresponding modes. */
! if (TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
! GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))))
! && num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0)))
! >= GET_MODE_BITSIZE (mode) + 1)
return gen_lowpart_for_combine (mode, XEXP (x, 0));
/* A truncate of a comparison can be replaced with a subreg if