Hi!
Many thanks for all your work on this.
On Mon, Jun 11, 2018 at 07:31:44PM -0400, Michael Meissner wrote:
> This patch is a complete rework of the previous patch. Previously I used new
> target hooks to provide IFmode (__ibm128) from being widened by default to
> TFmode (long double) on power9 systems when long double is IEEE 128-bit.
>
> This patch reorganizes the 3 128-bit floating point types, so that IFmode is
> numerically higher than TFmode/KFmode. This means IFmode is considered the
> widest type.
Sneaky. It probably helps. I like it :-)
> Since we do not define arithmetic insns for IFmode, other than
> negate/absolute value (that we define for the other types), we will not have
> undesirable widening.
I don't understand this part. We _do_ need to have all the basic operations
for IFmode. How else can __ibm128 variables work (with -mabi=ieeelongdouble)?
> @@ -865,9 +872,8 @@ extern unsigned char rs6000_recip_bits[]
> words. */
> #define DOUBLE_TYPE_SIZE 64
>
> -/* A C expression for the size in bits of the type `long double' on
> - the target machine. If you don't define this, the default is two
> - words. */
> +/* A C expression for the size in bits of the type `long double' on the
> target
> + machine. If you don't define this, the default is two words. */
Please don't change things that don't change anything.
> --- gcc/config/rs6000/rs6000.md (revision 261349)
> +++ gcc/config/rs6000/rs6000.md (working copy)
> @@ -8159,8 +8159,8 @@ (define_expand "extendtfkf2"
> })
>
> (define_expand "trunciftf2"
> - [(set (match_operand:IF 0 "gpc_reg_operand")
> - (float_truncate:IF (match_operand:TF 1 "gpc_reg_operand")))]
> + [(set (match_operand:TF 0 "gpc_reg_operand")
> + (float_truncate:TF (match_operand:IF 1 "gpc_reg_operand")))]
> "TARGET_FLOAT128_TYPE"
> {
> rs6000_expand_float128_convert (operands[0], operands[1], false);
> @@ -8168,8 +8168,8 @@ (define_expand "trunciftf2"
> })
>
> (define_expand "truncifkf2"
> - [(set (match_operand:IF 0 "gpc_reg_operand")
> - (float_truncate:IF (match_operand:KF 1 "gpc_reg_operand")))]
> + [(set (match_operand:KF 0 "gpc_reg_operand")
> + (float_truncate:KF (match_operand:IF 1 "gpc_reg_operand")))]
> "TARGET_FLOAT128_TYPE"
> {
> rs6000_expand_float128_convert (operands[0], operands[1], false);
These bugfixes really should have been a separate patch.
Please explain that IFmode arith part?
Segher
