On Mon, Aug 08, 2016 at 12:55:59PM +0930, Alan Modra wrote:
> On Mon, Aug 08, 2016 at 12:13:18PM +0930, Alan Modra wrote:
> > This patch fixes a case where reload blindly assumes a subreg mem
> > is OK if its address has been partially reloaded by
> > legitimize_reload_address. The change ought to be fairly obvious
> > considering that the analogous non-subreg case only gives a win to
> > address_reloaded[i] == 1. Bootstrapped and regression tested
> > powerpc64le-linux using
> > RUNTESTFLAGS="--target_board=unix'{-mlra,-mno-lra}'"
> > to run the testsuite using both lra and reload. OK for mainline
> > and active branches?
>
> When I look at the correct bootstrap I see I have some regressions.
> Sorry for the noise, patch withdrawn.
Hi Ulrich, Bernd,
It turns out that the patch just exposed an existing rs6000 backend
problem, that made the result of forcing a constant to memory invalid
even for the "m" constraint. So please consider the patch again.
Segher, is this rs6000 patch OK? Bootstrapped as above.
PR target/72771
* config/rs6000/rs6000.c (toc_relative_expr_p): Allow lo_sum/high
toc refs created during reload.
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 7176939..8b8997b 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -7938,8 +7938,8 @@ constant_pool_expr_p (rtx op)
static const_rtx tocrel_base, tocrel_offset;
/* Return true if OP is a toc pointer relative address (the output
- of create_TOC_reference). If STRICT, do not match high part or
- non-split -mcmodel=large/medium toc pointer relative addresses. */
+ of create_TOC_reference). If STRICT, do not match non-split
+ -mcmodel=large/medium toc pointer relative addresses. */
bool
toc_relative_expr_p (const_rtx op, bool strict)
@@ -7949,13 +7949,17 @@ toc_relative_expr_p (const_rtx op, bool strict)
if (TARGET_CMODEL != CMODEL_SMALL)
{
- /* Only match the low part. */
- if (GET_CODE (op) == LO_SUM
- && REG_P (XEXP (op, 0))
- && INT_REG_OK_FOR_BASE_P (XEXP (op, 0), strict))
- op = XEXP (op, 1);
- else if (strict)
+ /* When strict ensure we have everything tidy. */
+ if (strict
+ && !(GET_CODE (op) == LO_SUM
+ && REG_P (XEXP (op, 0))
+ && INT_REG_OK_FOR_BASE_P (XEXP (op, 0), strict)))
return false;
+
+ /* When not strict, allow non-split toc addresses and also allow
+ lo_sum/high addresses created during reload. */
+ if (GET_CODE (op) == LO_SUM)
+ op = XEXP (op, 1);
}
tocrel_base = op;
--
Alan Modra
Australia Development Lab, IBM
