Re: [PATCH] Don't simplify NAN/INF or out-of-range constant for FIX/UNSIGNED_FIX.

[Jeff Law <jeffreyalaw@gmail.com>]

On 5/26/24 7:08 PM, liuhongt wrote:
> Update in V2:
> Guard constant folding for overflow value in
> fold_convert_const_int_from_real with flag_trapping_math.
> Add -fno-trapping-math to related testcases which warn for overflow
> in conversion from floating point to integer.
> 
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> Ok for trunk?
> 
> According to IEEE standard, for conversions from floating point to
> integer. When a NaN or infinite operand cannot be represented in the
> destination format and this cannot otherwise be indicated, the invalid
> operation exception shall be signaled. When a numeric operand would
> convert to an integer outside the range of the destination format, the
> invalid operation exception shall be signaled if this situation cannot
> otherwise be indicated.
> 
> The patch prevent simplication of the conversion from floating point
> to integer for NAN/INF/out-of-range constant when flag_trapping_math.
> 
> gcc/ChangeLog:
> 
> 	PR rtl-optimization/100927
> 	PR rtl-optimization/115161
> 	PR rtl-optimization/115115
> 	* simplify-rtx.cc (simplify_const_unary_operation): Prevent
> 	simplication of FIX/UNSIGNED_FIX for NAN/INF/out-of-range
> 	constant when flag_trapping_math.
> 	* fold-const.cc (fold_convert_const_int_from_real): Don't fold
> 	for overflow value when_trapping_math.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.dg/pr100927.c: New test.
> 	* c-c++-common/Wconversion-1.c: Add -fno-trapping-math.
> 	* c-c++-common/dfp/convert-int-saturate.c: Ditto.
> 	* g++.dg/ubsan/pr63956.C: Ditto.
> 	* g++.dg/warn/Wconversion-real-integer.C: Ditto.
> 	* gcc.c-torture/execute/20031003-1.c: Ditto.
> 	* gcc.dg/Wconversion-complex-c99.c: Ditto.
> 	* gcc.dg/Wconversion-real-integer.c: Ditto.
> 	* gcc.dg/c90-const-expr-11.c: Ditto.
> 	* gcc.dg/overflow-warn-8.c: Ditto.
OK.  Thanks.

jeff