From 676e38c2a93311bc847c1034637efc935e527f8f Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Tue, 1 Oct 2019 11:36:47 +0000 Subject: [PATCH] Store float for pow result test Optimizing gcc.dg/torture/pr41094.c, the compiler computes the constant value and short-circuits the whole thing. At -O0, however, on 32-bit x86, the call to pow() remains, and the program compares the returned value in a stack register, with excess precision, with the exact return value expected from pow(). If libm's pow() returns a slightly off result, the compare fails. If the value in the register is stored in a separate variable, so it gets rounded to double precision, and then compared, the compare passes. It's not clear that the test was meant to detect libm's reliance on rounding off the excess precision, but I guess it wasn't, so I propose this slight change that enables it to pass regardless of the slight inaccuracy of the C library in use. for gcc/testsuite/ChangeLog * gcc.dg/torture/pr41094.c: Introduce intermediate variable. From-SVN: r276404 --- gcc/testsuite/ChangeLog | 2 ++ gcc/testsuite/gcc.dg/torture/pr41094.c | 3 ++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 99230295d7c..4f876e543ea 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,7 @@ 2019-10-01 Alexandre Oliva + * gcc.dg/torture/pr41094.c: Introduce intermediate variable. + PR debug/91507 * gcc.dg/debug/dwarf2/array-0.c: New. * gcc.dg/debug/dwarf2/array-1.c: New. diff --git a/gcc/testsuite/gcc.dg/torture/pr41094.c b/gcc/testsuite/gcc.dg/torture/pr41094.c index 2a4e9616cbf..9219a1741a3 100644 --- a/gcc/testsuite/gcc.dg/torture/pr41094.c +++ b/gcc/testsuite/gcc.dg/torture/pr41094.c @@ -13,7 +13,8 @@ double foo(void) int main() { - if (foo() != 2.0) + double r = foo (); + if (r != 2.0) abort (); return 0; }