r255188 - in /trunk/gcc: ChangeLog config/rs600...

Tue Nov 28 01:28:00 GMT 2017

Author: segher
Date: Tue Nov 28 01:28:57 2017
New Revision: 255188

URL: https://gcc.gnu.org/viewcvs?rev=255188&root=gcc&view=rev
Log:
rs6000: Improve comparison rtx_cost (PR81288)

The current rs6000 rtx_cost for comparisons against 0 is very high if
TARGET_ISEL && !TARGET_MFCRF, much higher than for reg-reg comparisons,
much higher than a load of 0 and such a reg-reg-comparison.  This leads
to infinite recursion in CSE (see PR81288).

This patch removes the too-high cost, also simplifying this code.

	PR 81288/target
	* config/rs6000/rs6000.c (rs6000_rtx_costs): Do not handle
	TARGET_ISEL && !TARGET_MFCRF differently.  Simplify code.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/rs6000/rs6000.c