On ARM soft-float, the float to double conversion doesn't convert a sNaN
to qNaN as the IEEE Std 754 standard mandates:
"Under default exception handling, any operation signaling an invalid
operation exception and for which a floating-point result is to be
delivered shall deliver a quiet NaN."
Given the soft float ARM code ignores exceptions and always provides a
result, a float to double conversion of a signaling NaN should return a
quiet NaN. Fix this in extendsfdf2.
2014-05-18 Aurelien Jarno <aurel...@aurel32.net>
PR target/61219
* config/arm/ieee754-df.S (extendsfdf2): Convert sNaN to qNaN.
Index: libgcc/config/arm/ieee754-df.S
===================================================================
--- libgcc/config/arm/ieee754-df.S (revision 210588)
+++ libgcc/config/arm/ieee754-df.S (working copy)
@@ -473,11 +473,15 @@
eorne xh, xh, #0x38000000 @ fixup exponent otherwise.
RETc(ne) @ and return it.
- teq r2, #0 @ if actually 0
- do_it ne, e
- teqne r3, #0xff000000 @ or INF or NAN
+ bics r2, r2, #0xff000000 @ isolate mantissa
+ do_it eq @ if 0, that is ZERO or INF,
RETc(eq) @ we are done already.
+ teq r3, #0xff000000 @ check for NAN
+ do_it eq, t
+ orreq xh, xh, #0x00080000 @ change to quiet NAN
+ RETc(eq) @ and return it.
+
@ value was denormalized. We can normalize it now.
do_push {r4, r5, lr}
mov r4, #0x380 @ setup corresponding exponent
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
aurel...@aurel32.net http://www.aurel32.net
