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Fix spurious overflow exceptions from x86/x86_64 powl (bug 13872).
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Joseph Myers
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@ -1,5 +1,13 @@
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2012-04-09 Joseph Myers <joseph@codesourcery.com>
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[BZ #13872]
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* sysdeps/i386/fpu/e_powl.S (p78): New object.
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(__ieee754_powl): Saturate large exponents rather than testing for
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overflow of y*log2(x).
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* sysdeps/x86_64/fpu/e_powl.S: Likewise.
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* math/libm-test.inc (pow_test): Do not permit spurious overflow
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exceptions.
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[BZ #11521]
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* math/s_ctan.c: Include <float.h>.
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(__ctan): Avoid internal overflow or cancellation in calculating
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7
NEWS
7
NEWS
@ -18,9 +18,10 @@ Version 2.16
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13530, 13531, 13532, 13533, 13547, 13551, 13552, 13553, 13555, 13559,
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13566, 13583, 13592, 13618, 13637, 13656, 13658, 13673, 13691, 13695,
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13704, 13705, 13706, 13726, 13738, 13760, 13761, 13786, 13792, 13806,
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13824, 13840, 13841, 13844, 13846, 13851, 13852, 13854, 13871, 13873,
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13879, 13883, 13892, 13895, 13908, 13910, 13911, 13912, 13913, 13915,
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13916, 13917, 13918, 13919, 13920, 13921, 13926, 13928, 13938, 13963
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13824, 13840, 13841, 13844, 13846, 13851, 13852, 13854, 13871, 13872,
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13873, 13879, 13883, 13892, 13895, 13908, 13910, 13911, 13912, 13913,
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13915, 13916, 13917, 13918, 13919, 13920, 13921, 13926, 13928, 13938,
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13963
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* ISO C11 support:
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@ -5682,8 +5682,7 @@ pow_test (void)
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TEST_ff_f (pow, 0x1p72L, 0x1p72L, plus_infty, OVERFLOW_EXCEPTION);
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TEST_ff_f (pow, 10, -0x1p72L, 0);
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TEST_ff_f (pow, max_value, max_value, plus_infty, OVERFLOW_EXCEPTION);
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/* Bug 13872: spurious OVERFLOW exception may be present. */
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TEST_ff_f (pow, 10, -max_value, 0, OVERFLOW_EXCEPTION_OK);
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TEST_ff_f (pow, 10, -max_value, 0);
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TEST_ff_f (pow, 0, 1, 0);
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TEST_ff_f (pow, 0, 11, 0);
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@ -5997,8 +5996,7 @@ pow_test (void)
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TEST_ff_f (pow, -max_value, -0x1.ffffffffffffffffffffffffffffp+113L, plus_zero);
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# endif
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#endif
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/* Bug 13872: spurious OVERFLOW exception may be present. */
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TEST_ff_f (pow, -max_value, -max_value, plus_zero, OVERFLOW_EXCEPTION_OK);
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TEST_ff_f (pow, -max_value, -max_value, plus_zero);
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TEST_ff_f (pow, -max_value, 0xffffff, minus_infty, OVERFLOW_EXCEPTION);
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TEST_ff_f (pow, -max_value, 0x1fffffe, plus_infty, OVERFLOW_EXCEPTION);
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@ -6122,8 +6120,7 @@ pow_test (void)
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TEST_ff_f (pow, -min_value, 0x1.ffffffffffffffffffffffffffffp+113L, plus_zero);
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# endif
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#endif
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/* Bug 13872: spurious OVERFLOW exception may be present. */
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TEST_ff_f (pow, -min_value, max_value, plus_zero, OVERFLOW_EXCEPTION_OK);
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TEST_ff_f (pow, -min_value, max_value, plus_zero);
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#ifndef TEST_LDOUBLE /* Bug 13881. */
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TEST_ff_f (pow, 0x0.ffffffp0, 10, 0.999999403953712118183885036774764444747L);
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@ -35,6 +35,9 @@ p63: .byte 0, 0, 0, 0, 0, 0, 0xe0, 0x43
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ASM_TYPE_DIRECTIVE(p64,@object)
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p64: .byte 0, 0, 0, 0, 0, 0, 0xf0, 0x43
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ASM_SIZE_DIRECTIVE(p64)
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ASM_TYPE_DIRECTIVE(p78,@object)
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p78: .byte 0, 0, 0, 0, 0, 0, 0xd0, 0x44
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ASM_SIZE_DIRECTIVE(p78)
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.section .rodata.cst16,"aM",@progbits,16
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@ -166,6 +169,21 @@ ENTRY(__ieee754_powl)
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fxch // x : y
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fabs // |x| : y
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fxch // y : |x|
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// If y has absolute value at least 1L<<78, then any finite
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// nonzero x will result in 0 (underflow), 1 or infinity (overflow).
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// Saturate y to those bounds to avoid overflow in the calculation
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// of y*log2(x).
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fld %st // y : y : |x|
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fabs // |y| : y : |x|
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fcompl MO(p78) // y : |x|
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fnstsw
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sahf
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jc 3f
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fstp %st(0) // pop y
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fldl MO(p78) // 1L<<78 : |x|
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testb $2, %dl
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jz 3f // y > 0
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fchs // -(1L<<78) : |x|
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.align ALIGNARG(4)
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3: /* y is a real number. */
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fxch // x : y
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@ -185,11 +203,6 @@ ENTRY(__ieee754_powl)
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7: fyl2x // log2(x) : y
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8: fmul %st(1) // y*log2(x) : y
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fxam
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fnstsw
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andb $0x45, %ah
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cmpb $0x05, %ah // is y*log2(x) == ±inf ?
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je 28f
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fst %st(1) // y*log2(x) : y*log2(x)
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frndint // int(y*log2(x)) : y*log2(x)
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fsubr %st, %st(1) // int(y*log2(x)) : fract(y*log2(x))
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@ -198,13 +211,7 @@ ENTRY(__ieee754_powl)
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faddl MO(one) // 2^fract(y*log2(x)) : int(y*log2(x))
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fscale // 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
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fstp %st(1) // 2^fract(y*log2(x))*2^int(y*log2(x))
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jmp 29f
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28: fstp %st(1) // y*log2(x)
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fldl MO(one) // 1 : y*log2(x)
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fscale // 2^(y*log2(x)) : y*log2(x)
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fstp %st(1) // 2^(y*log2(x))
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29: testb $2, %dh
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testb $2, %dh
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jz 292f
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// x is negative. If y is an odd integer, negate the result.
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fldt 24(%esp) // y : abs(result)
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@ -35,6 +35,9 @@ p63: .byte 0, 0, 0, 0, 0, 0, 0xe0, 0x43
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ASM_TYPE_DIRECTIVE(p64,@object)
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p64: .byte 0, 0, 0, 0, 0, 0, 0xf0, 0x43
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ASM_SIZE_DIRECTIVE(p64)
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ASM_TYPE_DIRECTIVE(p78,@object)
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p78: .byte 0, 0, 0, 0, 0, 0, 0xd0, 0x44
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ASM_SIZE_DIRECTIVE(p78)
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.section .rodata.cst16,"aM",@progbits,16
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@ -151,6 +154,21 @@ ENTRY(__ieee754_powl)
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fxch // x : y
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fabs // |x| : y
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fxch // y : |x|
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// If y has absolute value at least 1L<<78, then any finite
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// nonzero x will result in 0 (underflow), 1 or infinity (overflow).
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// Saturate y to those bounds to avoid overflow in the calculation
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// of y*log2(x).
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fldl MO(p78) // 1L<<78 : y : |x|
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fld %st(1) // y : 1L<<78 : y : |x|
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fabs // |y| : 1L<<78 : y : |x|
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fcomip %st(1), %st // 1L<<78 : y : |x|
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fstp %st(0) // y : |x|
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jc 3f
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fstp %st(0) // pop y
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fldl MO(p78) // 1L<<78 : |x|
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testb $2, %dl
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jz 3f // y > 0
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fchs // -(1L<<78) : |x|
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.align ALIGNARG(4)
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3: /* y is a real number. */
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fxch // x : y
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@ -170,11 +188,6 @@ ENTRY(__ieee754_powl)
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7: fyl2x // log2(x) : y
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8: fmul %st(1) // y*log2(x) : y
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fxam
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fnstsw
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andb $0x45, %ah
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cmpb $0x05, %ah // is y*log2(x) == ±inf ?
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je 28f
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fst %st(1) // y*log2(x) : y*log2(x)
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frndint // int(y*log2(x)) : y*log2(x)
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fsubr %st, %st(1) // int(y*log2(x)) : fract(y*log2(x))
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@ -183,13 +196,7 @@ ENTRY(__ieee754_powl)
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faddl MO(one) // 2^fract(y*log2(x)) : int(y*log2(x))
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fscale // 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
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fstp %st(1) // 2^fract(y*log2(x))*2^int(y*log2(x))
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jmp 29f
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28: fstp %st(1) // y*log2(x)
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fldl MO(one) // 1 : y*log2(x)
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fscale // 2^(y*log2(x)) : y*log2(x)
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fstp %st(1) // 2^(y*log2(x))
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29: testb $2, %dh
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testb $2, %dh
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jz 292f
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// x is negative. If y is an odd integer, negate the result.
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fldt 24(%rsp) // y : abs(result)
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