diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/doc/rtl.texi | 18 | ||||
| -rw-r--r-- | gcc/read-rtl.c | 10 |
2 files changed, 28 insertions, 0 deletions
diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi index 4f9b990..7c12991 100644 --- a/gcc/doc/rtl.texi +++ b/gcc/doc/rtl.texi @@ -1711,6 +1711,24 @@ machine's or host machine's floating point format. To convert them to the precise bit pattern used by the target machine, use the macro @code{REAL_VALUE_TO_TARGET_DOUBLE} and friends (@pxref{Data Output}). +@findex const_double_zero +The host dependency for the number of integers used to store a double +value makes it problematic for machine descriptions to use expressions +of code @code{const_double} and therefore a syntactic alias has been +provided: + +@smallexample +(const_double_zero) +@end smallexample + +standing for: + +@smallexample +(const_double 0 0 @dots{}) +@end smallexample + +for matching the floating-point value zero, possibly the only useful one. + @findex CONST_WIDE_INT @item (const_wide_int:@var{m} @var{nunits} @var{elt0} @dots{}) This contains an array of @code{HOST_WIDE_INT}s that is large enough diff --git a/gcc/read-rtl.c b/gcc/read-rtl.c index 403f254..2922af5 100644 --- a/gcc/read-rtl.c +++ b/gcc/read-rtl.c @@ -1651,6 +1651,16 @@ rtx_reader::read_rtx_code (const char *code_name) return return_rtx; } + /* Handle "const_double_zero". */ + if (strcmp (code_name, "const_double_zero") == 0) + { + code = CONST_DOUBLE; + return_rtx = rtx_alloc (code); + memset (return_rtx, 0, RTX_CODE_SIZE (code)); + PUT_CODE (return_rtx, code); + return return_rtx; + } + /* If we end up with an insn expression then we free this space below. */ return_rtx = rtx_alloc_for_name (code_name); code = GET_CODE (return_rtx); |