https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98470
--- Comment #1 from jcmvbkbc at gcc dot gnu.org --- It happens at the reload pass when reload transforms the following RTL that comes to it from the IRA pass: (insn 20 163 164 30 (set (reg:SF 162 [ iftmp.0_87 ]) (mem/u/c:SF (symbol_ref/u:SI ("*.LC0") [flags 0x2]) [0 S4 A32])) "float-ice.c":11:17 45 {movsf_internal} (expr_list:REG_EQUIV (mem/u/c:SF (symbol_ref/u:SI ("*.LC0") [flags 0x2]) [0 S4 A32]) (nil))) ... (insn 538 168 169 32 (set (reg:SF 71 [ iftmp.0_87 ]) (reg:SF 162 [ iftmp.0_87 ])) "float-ice.c":11:17 45 {movsf_internal} (nil)) to the following RTL: (insn 538 168 169 32 (set (reg:SF 19 f0 [orig:71 iftmp.0_87 ] [71]) (mem/u/c:SF (symbol_ref/u:SI ("*.LC0") [flags 0x2]) [0 S4 A32])) "float-ice.c":11:17 45 {movsf_internal} (nil)) which tries to load a literal into a hardware FP register. There's no opcode for it in the xtensa ISA, there's no constraint that would match it in the movsf_internal and the predicate in this instruction definition evaluates to false on such input, but the substitution happens anyway.