re PR rtl-optimization/89445 (_mm512_maskz_loadu_pd "forgets" to use the mask)

re PR rtl-optimization/89445 (_mm512_maskz_loadu_pd "forgets" to use the mask)

	PR rtl-optimization/89445
	* simplify-rtx.c (simplify_ternary_operation): Don't use
	simplify_merge_mask on operands that may trap.
	* rtlanal.c (may_trap_p_1): Use FLOAT_MODE_P instead of
	SCALAR_FLOAT_MODE_P checks.  For integral division by zero, if
	second operand is CONST_VECTOR, check if any element could be zero.
	Don't expect traps for VEC_{MERGE,SELECT,CONCAT,DUPLICATE} unless
	their operands can trap.

	* gcc.target/i386/avx512f-pr89445.c: New test.

From-SVN: r269176