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| author | Roger Sayle <roger@nextmovesoftware.com> | 2022-05-30 21:32:58 +0100 |
|---|---|---|
| committer | Roger Sayle <roger@nextmovesoftware.com> | 2022-05-30 21:38:33 +0100 |
| commit | 1ad584d538d349db13cfa8440222d91d5e9aff3f (patch) | |
| tree | fafc4030713f8bbde964105668e4fca5a487c889 | |
| parent | 871dbb6112e22ff92914613c332944fd19dd39a8 (diff) | |
| download | gcc-1ad584d538d349db13cfa8440222d91d5e9aff3f.zip gcc-1ad584d538d349db13cfa8440222d91d5e9aff3f.tar.gz gcc-1ad584d538d349db13cfa8440222d91d5e9aff3f.tar.bz2 | |
Allow SCmode and DImode to be tieable with TARGET_64BIT on x86_64.
This patch is a form of insurance policy in case my patch for PR 7061 runs
into problems on non-x86 targets; the middle-end can add an extra check
that the backend is happy placing SCmode and DImode values in the same
register, before creating a SUBREG. Unfortunately, ix86_modes_tieable_p
currently claims this is not allowed(?), even though the default target
hook for modes_tieable_p is to always return true [i.e. false can be
used to specifically prohibit bad combinations], and the x86_64 ABI
passes SCmode values in DImode registers!. This makes the backend's
modes_tiable_p hook a little more forgiving, and additionally enables
interconversion between SCmode and V2SFmode, and between DCmode and
VD2Fmode, which opens interesting opporutunities in the future.
2022-05-30 Roger Sayle <roger@nextmovesoftware.com>
gcc/ChangeLog
* config/i386/i386.cc (ix86_modes_tieable_p): Allow SCmode to be
tieable with DImode on TARGET_64BIT, and SCmode tieable with
V2SFmode, and DCmode with V2DFmode.
| -rw-r--r-- | gcc/config/i386/i386.cc | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc index daa60ac..df5c80d 100644 --- a/gcc/config/i386/i386.cc +++ b/gcc/config/i386/i386.cc @@ -20141,6 +20141,18 @@ ix86_modes_tieable_p (machine_mode mode1, machine_mode mode2) return (GET_MODE_SIZE (mode1) == 8 && ix86_hard_regno_mode_ok (FIRST_MMX_REG, mode1)); + /* SCmode and DImode can be tied. */ + if ((mode1 == E_SCmode && mode2 == E_DImode) + || (mode1 == E_DImode && mode2 == E_SCmode)) + return TARGET_64BIT; + + /* [SD]Cmode and V2[SD]Fmode modes can be tied. */ + if ((mode1 == E_SCmode && mode2 == E_V2SFmode) + || (mode1 == E_V2SFmode && mode2 == E_SCmode) + || (mode1 == E_DCmode && mode2 == E_V2DFmode) + || (mode1 == E_V2DFmode && mode2 == E_DCmode)) + return true; + return false; } |