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| author | Richard Henderson <rth@redhat.com> | 2003-02-05 14:37:54 -0800 |
|---|---|---|
| committer | Richard Henderson <rth@gcc.gnu.org> | 2003-02-05 14:37:54 -0800 |
| commit | 7dba8395e27f52d22aa11ff2fc147858e34f2a9d (patch) | |
| tree | e14ea46575bce454a67edbb9d6bc03000c970bcd /gcc/doc/tm.texi | |
| parent | 8d705469aaefd27a439760de0c216ff036f92e11 (diff) | |
| download | gcc-7dba8395e27f52d22aa11ff2fc147858e34f2a9d.zip gcc-7dba8395e27f52d22aa11ff2fc147858e34f2a9d.tar.gz gcc-7dba8395e27f52d22aa11ff2fc147858e34f2a9d.tar.bz2 | |
defaults.h (CLZ_DEFINED_VALUE_AT_ZERO): New.
* defaults.h (CLZ_DEFINED_VALUE_AT_ZERO): New.
(CTZ_DEFINED_VALUE_AT_ZERO): New.
* doc/rtl.texi, doc/tm.texi: Document them.
* combine.c (nonzero_bits) [CLZ, CTZ]: Handle the definedness
of the value at zero properly.
* fold-const.c (tree_expr_nonnegative_p): Likewise.
* simplify-rtx.c (simplify_unary_operation): Likewise.
* config/alpha/alpha.h (CLZ_DEFINED_VALUE_AT_ZERO): New.
(CTZ_DEFINED_VALUE_AT_ZERO): New.
* config/arm/arm.c (TARGET_INIT_BUILTINS): Remove.
(TARGET_EXPAND_BUILTIN): Remove.
(def_builtin, arm_init_builtins, arm_expand_builtin): Remove.
* config/arm/arm.h (CLZ_DEFINED_VALUE_AT_ZERO): New.
(enum arm_builtins): Remove.
* config/arm/arm.md (UNSPEC_CLZ): Remove.
(clzsi2): Rename from clz; use clz instead of unspec.
(ctzsi2): New.
* config/arm/arm-protos.h: Update.
From-SVN: r62453
Diffstat (limited to 'gcc/doc/tm.texi')
| -rw-r--r-- | gcc/doc/tm.texi | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi index b5cb240..0abf394 100644 --- a/gcc/doc/tm.texi +++ b/gcc/doc/tm.texi @@ -8800,6 +8800,25 @@ Define this macro on machine that have comparison operations that return floating-point values. If there are no such operations, do not define this macro. +@findex CLZ_DEFINED_VALUE_AT_ZERO +@findex CTZ_DEFINED_VALUE_AT_ZERO +@item CLZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value}) +@itemx CTZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value}) +A C expression that evaluates to true if the architecture defines a value +for @code{clz} or @code{ctz} with a zero operand. If so, @var{value} +should be set to this value. If this macro is not defined, the value of +@code{clz} or @code{ctz} is assumed to be undefined. + +This macro must be defined if the target's expansion for @code{ffs} +relies on a particular value to get correct results. Otherwise it +is not necessary, though it may be used to optimize some corner cases. + +Note that regardless of this macro the ``definedness'' of @code{clz} +and @code{ctz} at zero do @emph{not} extend to the builtin functions +visible to the user. Thus one may be free to adjust the value at will +to match the target expansion of these operations without fear of +breaking the API. + @findex Pmode @item Pmode An alias for the machine mode for pointers. On most machines, define |