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| author | Jeffrey A Law <law@cygnus.com> | 1998-07-14 19:59:53 +0000 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 1998-07-14 13:59:53 -0600 |
| commit | 0deaf5908c667725a6bd0d0673c017a0bbf97c71 (patch) | |
| tree | a6126ff07e62c18744f8a9957bd972ff86ba3df3 /gcc | |
| parent | 2c43b71ae591716613d94d074132e9c9f3642c2d (diff) | |
| download | gcc-0deaf5908c667725a6bd0d0673c017a0bbf97c71.zip gcc-0deaf5908c667725a6bd0d0673c017a0bbf97c71.tar.gz gcc-0deaf5908c667725a6bd0d0673c017a0bbf97c71.tar.bz2 | |
extend.texi: Clarify some issues related to local variables assigned to explicit registers.
* extend.texi: Clarify some issues related to local variables
assigned to explicit registers.
From-SVN: r21159
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 3 | ||||
| -rw-r--r-- | gcc/extend.texi | 8 |
2 files changed, 10 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index cb6fb70..9ecf22f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -6,6 +6,9 @@ Tue Jul 14 14:15:30 1998 Nick Clifton <nickc@cygnus.com> Tue Jul 14 14:46:08 1998 Jeffrey A Law (law@cygnus.com) + * extend.texi: Clarify some issues related to local variables + assigned to explicit registers. + * mn10300.md (mulsi): Turn into expander + pattern. * mn10300.md (movsi, movsf, movdi, movdf): Remove "x" from I -> a diff --git a/gcc/extend.texi b/gcc/extend.texi index 5cf1b24..b867e9c 100644 --- a/gcc/extend.texi +++ b/gcc/extend.texi @@ -2593,7 +2593,9 @@ very often. Local register variables in specific registers do not reserve the registers. The compiler's data flow analysis is capable of determining where the specified registers contain live values, and where they are -available for other uses. +available for other uses. Stores into local register variables may deleted +when they appear to be dead according to dataflow analysis. References +to local register variables may be deleted or moved or simplified. These local variables are sometimes convenient for use with the extended @code{asm} feature (@pxref{Extended Asm}), if you want to write one @@ -2744,6 +2746,10 @@ this variable in the register you specify at all times. You may not code an explicit reference to this register in an @code{asm} statement and assume it will always refer to this variable. +Stores into local register variables may deleted when they appear to be dead +according to dataflow analysis. References to local register variables may +be deleted or moved or simplified. + @node Alternate Keywords @section Alternate Keywords @cindex alternate keywords |