| Message ID | 20161128135819.GE427@x4 |
|---|---|
| State | New |
| Headers | show |
Hi Markus, On Mon, Nov 28, 2016 at 02:58:19PM +0100, Markus Trippelsdorf wrote: > Running bootstrap-ubsan on ppc64le shows many instances of e.g.: > config/rs6000/rs6000.c:6217:36: runtime error: left shift of negative value -12301 > > The attached patch fixes the issue and was tested on ppc64le. Thanks for the patch. for (i = 2; i <= copies; i *= 2) { HOST_WIDE_INT small_val; bitsize /= 2; small_val = splat_val >> bitsize; > bitsize /= 2; > small_val = splat_val >> bitsize; > mask >>= bitsize; > - if (splat_val != ((small_val << bitsize) | (small_val & mask))) > + if (splat_val != ((HOST_WIDE_INT) > + ((unsigned HOST_WIDE_INT) small_val << bitsize) > + | (small_val & mask))) > return false; > splat_val = small_val; > } Can't you just make small_val an unsigned WIDE_INT, instead? Segher
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 6c28e6a..dfb5dc8 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -6214,7 +6214,9 @@ vspltis_constant (rtx op, unsigned step, unsigned copies) bitsize /= 2; small_val = splat_val >> bitsize; mask >>= bitsize; - if (splat_val != ((small_val << bitsize) | (small_val & mask))) + if (splat_val != ((HOST_WIDE_INT) + ((unsigned HOST_WIDE_INT) small_val << bitsize) + | (small_val & mask))) return false; splat_val = small_val; }
Running bootstrap-ubsan on ppc64le shows many instances of e.g.: config/rs6000/rs6000.c:6217:36: runtime error: left shift of negative value -12301 The attached patch fixes the issue and was tested on ppc64le. OK for trunk? Thanks. PR target/78556 * config/rs6000/rs6000.h (vspltis_constant): Add casts to avoid left shifting of negative values. -- Markus