From b899fd784b2e89080c853afd5bb1776328c9d4e7 Mon Sep 17 00:00:00 2001 From: Joern Rennecke Date: Wed, 19 Jan 2011 15:23:06 +0000 Subject: [PATCH] tm.texi.in: Spell out that a lack of register class unions can lead to ICEs. * doc/tm.texi.in: Spell out that a lack of register class unions can lead to ICEs. * doc/tm.texi: Regenerate. From-SVN: r168998 --- gcc/ChangeLog | 6 ++++++ gcc/doc/tm.texi | 4 +++- gcc/doc/tm.texi.in | 4 +++- 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index b799162..9af2456 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2011-01-19 Joern Rennecke + + * doc/tm.texi.in: Spell out that a lack of register class unions + can lead to ICEs. + * doc/tm.texi: Regenerate. + 2011-01-19 Jakub Jelinek PR rtl-optimization/47337 diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi index 010e77b..e3325b0 100644 --- a/gcc/doc/tm.texi +++ b/gcc/doc/tm.texi @@ -2341,7 +2341,9 @@ You should define a class for the union of two classes whenever some instruction allows both classes. For example, if an instruction allows either a floating point (coprocessor) register or a general register for a certain operand, you should define a class @code{FLOAT_OR_GENERAL_REGS} -which includes both of them. Otherwise you will get suboptimal code. +which includes both of them. Otherwise you will get suboptimal code, +or even internal compiler errors when reload cannot find a register in the +the class computed via @code{reg_class_subunion}. You must also specify certain redundant information about the register classes: for each class, which classes contain it and which ones are diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in index 3298c3d..1a5f040 100644 --- a/gcc/doc/tm.texi.in +++ b/gcc/doc/tm.texi.in @@ -2331,7 +2331,9 @@ You should define a class for the union of two classes whenever some instruction allows both classes. For example, if an instruction allows either a floating point (coprocessor) register or a general register for a certain operand, you should define a class @code{FLOAT_OR_GENERAL_REGS} -which includes both of them. Otherwise you will get suboptimal code. +which includes both of them. Otherwise you will get suboptimal code, +or even internal compiler errors when reload cannot find a register in the +the class computed via @code{reg_class_subunion}. You must also specify certain redundant information about the register classes: for each class, which classes contain it and which ones are -- 2.7.4