https://gcc.gnu.org/g:12e18bc8d43214b39870d52405eb714a0c7f787d
commit 12e18bc8d43214b39870d52405eb714a0c7f787d Author: Michael Meissner <[email protected]> Date: Fri Feb 13 12:15:10 2026 -0500 Add support for dense math registers. This patch adds the -mdense-math option for -mcpu=future. The next set of patches will support for using dense math registers with the MMA instructions. gcc/ 2026-02-13 Michael Meissner <[email protected]> * config/rs6000/rs6000-c.cc (rs6000_define_or_undefine_macro): Define __DENSE_MATH__ if we have dense math registers. * config/rs6000/rs6000.cc (rs6000_option_override_internal): Do not allow -mdense-math unless -mcpu=future is used. (rs6000_opt_masks): Add -mdense-math support. * config/rs6000/rs6000.opt (-mdense-math): New option. * doc/invoke.texi (RS/6000 and PowerPC Options): Add -mdense-math. Diff: --- gcc/config/rs6000/rs6000-c.cc | 4 ++++ gcc/config/rs6000/rs6000.cc | 10 ++++++++++ gcc/config/rs6000/rs6000.opt | 4 ++++ gcc/doc/invoke.texi | 7 +++++++ 4 files changed, 25 insertions(+) diff --git a/gcc/config/rs6000/rs6000-c.cc b/gcc/config/rs6000/rs6000-c.cc index eb6a881aa9bd..a7eb951b014d 100644 --- a/gcc/config/rs6000/rs6000-c.cc +++ b/gcc/config/rs6000/rs6000-c.cc @@ -590,6 +590,10 @@ rs6000_target_modify_macros (bool define_p, HOST_WIDE_INT flags) /* Tell the user if we support the MMA instructions. */ if ((flags & OPTION_MASK_MMA) != 0) rs6000_define_or_undefine_macro (define_p, "__MMA__"); + /* Tell the user if we support the dense math registers for use with MMA and + cryptography. */ + if ((flags & OPTION_MASK_DENSE_MATH) != 0) + rs6000_define_or_undefine_macro (define_p, "__DENSE_MATH__"); /* Whether pc-relative code is being generated. */ if ((flags & OPTION_MASK_PCREL) != 0) rs6000_define_or_undefine_macro (define_p, "__PCREL__"); diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc index 3454a090dbc2..68d5e95179f7 100644 --- a/gcc/config/rs6000/rs6000.cc +++ b/gcc/config/rs6000/rs6000.cc @@ -4410,6 +4410,15 @@ rs6000_option_override_internal (bool global_init_p) if (!TARGET_PCREL && TARGET_PCREL_OPT) rs6000_isa_flags &= ~OPTION_MASK_PCREL_OPT; + /* Turn off dense math register support on non-future systems. */ + if (TARGET_DENSE_MATH && !TARGET_FUTURE) + { + if ((rs6000_isa_flags_explicit & OPTION_MASK_DENSE_MATH) != 0) + error ("%qs requires %qs", "-mdense-math", "-mcpu=future"); + + rs6000_isa_flags &= ~OPTION_MASK_DENSE_MATH; + } + if (TARGET_DEBUG_REG || TARGET_DEBUG_TARGET) rs6000_print_isa_options (stderr, 0, "after subtarget", rs6000_isa_flags); @@ -24463,6 +24472,7 @@ static struct rs6000_opt_mask const rs6000_opt_masks[] = false, true }, { "cmpb", OPTION_MASK_CMPB, false, true }, { "crypto", OPTION_MASK_CRYPTO, false, true }, + { "dense-math", OPTION_MASK_DENSE_MATH, false, true }, { "direct-move", 0, false, true }, { "dlmzb", OPTION_MASK_DLMZB, false, true }, { "efficient-unaligned-vsx", OPTION_MASK_EFFICIENT_UNALIGNED_VSX, diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt index 9f3519da77b2..f836d1982877 100644 --- a/gcc/config/rs6000/rs6000.opt +++ b/gcc/config/rs6000/rs6000.opt @@ -639,6 +639,10 @@ mieee128-constant Target Var(TARGET_IEEE128_CONSTANT) Init(1) Save Generate (do not generate) code that uses the LXVKQ instruction. +mdense-math +Target Mask(DENSE_MATH) Var(rs6000_isa_flags) +Generate (do not generate) instructions that use dense math registers. + ; Documented parameters -param=rs6000-vect-unroll-limit= diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index b574f85cc3f4..120f76a6f18f 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -32674,6 +32674,13 @@ This option is enabled by default. Enable or disable warnings about deprecated @samp{vector long ...} Altivec type usage. This option is enabled by default. +@opindex mdense-math +@opindex mno-dense-math +@item -mdense-math +@itemx -mno-dense-math +Generate (do not generate) code that uses the dense math registers. +This option is enabled by default. + @end table @node RX Options
