| Message ID | DB5PR08MB10308CC5C9BE873A3334E07B839A0@DB5PR08MB1030.eurprd08.prod.outlook.com |
|---|---|
| State | New |
| Headers | show |
| Series | [AArch64] Fix generation of tst (PR87763) | expand |
On 24/01/2019 15:36, Wilco Dijkstra wrote: > The TST instruction no longer matches in all cases due to changes in > Combine. The fix is simple, we now need to allow a subreg as well when > selecting the cc_mode. This fixes the tst_5.c and tst_6.c failures. > > AArch64 regress & bootstrap OK. > > ChangeLog: > 2019-01-23 Wilco Dijkstra <wdijkstr@arm.com> > > PR rtl-optimization/87763 > * config/aarch64/aarch64.c (aarch64_select_cc_mode): > Allow SUBREG when matching CC_NZmode compare. > > -- > > diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c > index a0006dc1f8a921dd83209d4404132a1fe3cfcd1e..237428d28b4f20ddfefee83ed020e209011147a0 100644 > --- a/gcc/config/aarch64/aarch64.c > +++ b/gcc/config/aarch64/aarch64.c > @@ -7120,7 +7120,7 @@ aarch64_select_cc_mode (RTX_CODE code, rtx x, rtx y) > > /* Equality comparisons of short modes against zero can be performed > using the TST instruction with the appropriate bitmask. */ > - if (y == const0_rtx && REG_P (x) > + if (y == const0_rtx && (REG_P (x) || SUBREG_P (x)) > && (code == EQ || code == NE) > && (GET_MODE (x) == HImode || GET_MODE (x) == QImode)) > return CC_NZmode; > OK. R.
On Thu, Jan 24, 2019 at 03:36:46PM +0000, Wilco Dijkstra wrote: > The TST instruction no longer matches in all cases due to changes in > Combine. The fix is simple, we now need to allow a subreg as well when > selecting the cc_mode. You needed to before, it just wasn't as obvious yet. It now is exposed in the simplest testcases (hard regs, as you used to have from function arguments here, can be referred to in any mode, without subreg). Segher
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index a0006dc1f8a921dd83209d4404132a1fe3cfcd1e..237428d28b4f20ddfefee83ed020e209011147a0 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -7120,7 +7120,7 @@ aarch64_select_cc_mode (RTX_CODE code, rtx x, rtx y) /* Equality comparisons of short modes against zero can be performed using the TST instruction with the appropriate bitmask. */ - if (y == const0_rtx && REG_P (x) + if (y == const0_rtx && (REG_P (x) || SUBREG_P (x)) && (code == EQ || code == NE) && (GET_MODE (x) == HImode || GET_MODE (x) == QImode)) return CC_NZmode;