| Message ID | 87bmm8grsj.fsf@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Prevent invalid register mode changes in combine | expand |
On 09/18/2017 05:38 AM, Richard Sandiford wrote: > This patch stops combine from changing the mode of an existing register > in-place if doing so would change the size of the underlying register > allocation size, as given by REGMODE_NATURAL_SIZE. Without this, > many tests fail in adjust_reg_mode after SVE is added. One example > is gcc.c-torture/compile/20090401-1.c. > > Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu. > Also tested by comparing the testsuite assembly output on at least one > target per CPU directory. OK to install? > > Richard > > > 2017-09-18 Richard Sandiford <richard.sandiford@linaro.org> > Alan Hayward <alan.hayward@arm.com> > David Sherwood <david.sherwood@arm.com> > > gcc/ > * combine.c (can_change_dest_mode): Reject changes in > REGMODE_NATURAL_SIZE. OK. jeff
Index: gcc/combine.c =================================================================== --- gcc/combine.c 2017-09-18 12:31:05.459555526 +0100 +++ gcc/combine.c 2017-09-18 12:31:05.604645232 +0100 @@ -2451,6 +2451,12 @@ can_change_dest_mode (rtx x, int added_s if (!REG_P (x)) return false; + /* Don't change between modes with different underlying register sizes, + since this could lead to invalid subregs. */ + if (REGMODE_NATURAL_SIZE (mode) + != REGMODE_NATURAL_SIZE (GET_MODE (x))) + return false; + regno = REGNO (x); /* Allow hard registers if the new mode is legal, and occupies no more registers than the old mode. */