From ee573dca11f327566829d93d8130f745b03f16a4 Mon Sep 17 00:00:00 2001 From: Harald van Dijk Date: Fri, 22 Nov 2019 00:27:39 +0100 Subject: [PATCH] doc: Remove claim about ISO C The patch to make -fcommon the default introduces a bogus claim into the GCC documentation. -fcommon was claimed to be incompatible with ISO C for preventing duplicate definitions from being diagnosed. It does, but as that elicits undefined behaviour (the requirement that there shall be no more than one external definition is not a constraint), ISO C does not require any diagnostic for it. In the absence of any other rule this would violate, both -fcommon and -fno-common are fully compatible with all versions of ISO C. 2019-11-21 Harald van Dijk * doc/invoke.texi (-fcommon): Remove claim about ISO C. From-SVN: r278604 --- gcc/ChangeLog | 4 ++++ gcc/doc/invoke.texi | 6 +++--- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2ccdedb5611..8389a86387d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2019-11-21 Harald van Dijk + + * doc/invoke.texi (-fcommon): Remove claim about ISO C. + 2019-11-21 Joseph Myers * gimplify.c (expand_FALLTHROUGH_r, expand_FALLTHROUGH): Use diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index c162b0d2643..34549e0d43c 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -14141,9 +14141,9 @@ than one compilation unit. The @option{-fcommon} places uninitialized global variables in a common block. This allows the linker to resolve all tentative definitions of the same variable in different compilation units to the same object, or to a non-tentative -definition. This behavior does not conform to ISO C, is inconsistent with C++, -and on many targets implies a speed and code size penalty on global variable -references. It is mainly useful to enable legacy code to link without errors. +definition. This behavior is inconsistent with C++, and on many targets implies +a speed and code size penalty on global variable references. It is mainly +useful to enable legacy code to link without errors. @item -fno-ident @opindex fno-ident -- 2.30.2