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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/simplify-rtx.c | |
| 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/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index 19d664b..0298b79e 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -449,14 +449,23 @@ simplify_unary_operation (code, mode, op, op_mode) case CLZ: arg0 &= GET_MODE_MASK (mode); - val = GET_MODE_BITSIZE (mode) - floor_log2 (arg0) - 1; + if (arg0 == 0 && CLZ_DEFINED_VALUE_AT_ZERO (mode, val)) + ; + else + val = GET_MODE_BITSIZE (mode) - floor_log2 (arg0) - 1; break; case CTZ: arg0 &= GET_MODE_MASK (mode); - val = arg0 == 0 - ? GET_MODE_BITSIZE (mode) - : exact_log2 (arg0 & -arg0); + if (arg0 == 0) + { + /* Even if the value at zero is undefined, we have to come + up with some replacement. Seems good enough. */ + if (! CTZ_DEFINED_VALUE_AT_ZERO (mode, val)) + val = GET_MODE_BITSIZE (mode); + } + else + val = exact_log2 (arg0 & -arg0); break; case POPCOUNT: |