From: Jakub Jelinek Date: Fri, 13 Oct 2017 20:14:34 +0000 (+0200) Subject: re PR target/82274 (__builtin_mul_overflow fails to detect overflow for int64_t when... X-Git-Tag: releases/gcc-6.5.0~739 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3133a20b90846c7d6bd69f4771a565574a189553;p=thirdparty%2Fgcc.git re PR target/82274 (__builtin_mul_overflow fails to detect overflow for int64_t when compiled with -m32) PR target/82274 * internal-fn.c (expand_mul_overflow): If both operands have the same highpart of -1 or 0 and the topmost bit of lowpart is different, overflow is if res <= 0 rather than res < 0. * libgcc2.c (__mulvDI3): If both operands have the same highpart of -1 and the topmost bit of lowpart is 0, multiplication overflows even if both lowparts are 0. * gcc.dg/pr82274-1.c: New test. * gcc.dg/pr82274-2.c: New test. From-SVN: r253743 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f67bef557bd3..e55d99a9b972 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2017-10-13 Jakub Jelinek + + PR target/82274 + * internal-fn.c (expand_mul_overflow): If both operands have + the same highpart of -1 or 0 and the topmost bit of lowpart + is different, overflow is if res <= 0 rather than res < 0. + 2017-10-10 Andreas Tobler * config.gcc: (armv7*-*-freebsd*): New target. diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c index 736012a139fc..2af0b45413f6 100644 --- a/gcc/internal-fn.c +++ b/gcc/internal-fn.c @@ -1565,8 +1565,8 @@ expand_mul_overflow (location_t loc, tree lhs, tree arg0, tree arg1, } /* At this point hipart{0,1} are both in [-1, 0]. If they are - the same, overflow happened if res is negative, if they are - different, overflow happened if res is positive. */ + the same, overflow happened if res is non-positive, if they + are different, overflow happened if res is positive. */ if (op0_sign != 1 && op1_sign != 1 && op0_sign != op1_sign) emit_jump (hipart_different); else if (op0_sign == 1 || op1_sign == 1) @@ -1574,7 +1574,7 @@ expand_mul_overflow (location_t loc, tree lhs, tree arg0, tree arg1, NULL_RTX, NULL, hipart_different, PROB_EVEN); - do_compare_rtx_and_jump (res, const0_rtx, LT, false, mode, + do_compare_rtx_and_jump (res, const0_rtx, LE, false, mode, NULL_RTX, NULL, do_error, PROB_VERY_UNLIKELY); emit_jump (done_label); diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index c53d6b168f83..332d709643e9 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2017-10-13 Jakub Jelinek + + PR target/82274 + * gcc.dg/pr82274-1.c: New test. + * gcc.dg/pr82274-2.c: New test. + 2017-10-06 Thomas Koenig Steven G. Kargl diff --git a/gcc/testsuite/gcc.dg/pr82274-1.c b/gcc/testsuite/gcc.dg/pr82274-1.c new file mode 100644 index 000000000000..f96b7338fc47 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr82274-1.c @@ -0,0 +1,16 @@ +/* PR target/82274 */ +/* { dg-do run } */ +/* { dg-shouldfail "trapv" } */ +/* { dg-options "-ftrapv" } */ + +int +main () +{ +#ifdef __SIZEOF_INT128__ + volatile __int128 m = -(((__int128) 1) << (__CHAR_BIT__ * __SIZEOF_INT128__ / 2)); +#else + volatile long long m = -(1LL << (__CHAR_BIT__ * __SIZEOF_LONG_LONG__ / 2)); +#endif + m = m * m; + return 0; +} diff --git a/gcc/testsuite/gcc.dg/pr82274-2.c b/gcc/testsuite/gcc.dg/pr82274-2.c new file mode 100644 index 000000000000..ccc55b50d94b --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr82274-2.c @@ -0,0 +1,22 @@ +/* PR target/82274 */ +/* { dg-do run } */ +/* { dg-options "-O2" } */ + +int +main () +{ +#ifdef __SIZEOF_INT128__ + __int128 m = -(((__int128) 1) << (__CHAR_BIT__ * __SIZEOF_INT128__ / 2)); + volatile __int128 mv = m; + __int128 r; +#else + long long m = -(1LL << (__CHAR_BIT__ * __SIZEOF_LONG_LONG__ / 2)); + volatile long long mv = m; + long long r; +#endif + if (!__builtin_mul_overflow (mv, mv, &r)) + __builtin_abort (); + if (!__builtin_mul_overflow (m, m, &r)) + __builtin_abort (); + return 0; +} diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog index d04836f070df..8b1238e907c7 100644 --- a/libgcc/ChangeLog +++ b/libgcc/ChangeLog @@ -1,3 +1,10 @@ +2017-10-13 Jakub Jelinek + + PR target/82274 + * libgcc2.c (__mulvDI3): If both operands have + the same highpart of -1 and the topmost bit of lowpart is 0, + multiplication overflows even if both lowparts are 0. + 2017-07-20 Peter Bergner Backport from mainline diff --git a/libgcc/libgcc2.c b/libgcc/libgcc2.c index 3797e046f924..0024a5756cb3 100644 --- a/libgcc/libgcc2.c +++ b/libgcc/libgcc2.c @@ -375,7 +375,8 @@ __mulvDI3 (DWtype u, DWtype v) } else { - if (uu.s.high == (Wtype) -1 && vv.s.high == (Wtype) - 1) + if ((uu.s.high & vv.s.high) == (Wtype) -1 + && (uu.s.low | vv.s.low) != 0) { DWunion ww = {.ll = (UDWtype) (UWtype) uu.s.low * (UDWtype) (UWtype) vv.s.low};