tcg: Allocate TEMP_VAL_MEM frame in temp_load()

Be sure to allocate the temp frame if it wasn't.

In the resolved issues, incomplete dead code elimination left a load
at the top of an unreachable loop.  We simply need to allocate the
stack slot to avoid crashing.

Fixes: c896fe29d6c ("TCG code generator")
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Reported-by: Helge Konetzka <hk@zapateado.de>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2891
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2899
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250401144332.41615-1-philmd@linaro.org>

tcg/tcg.c

@@ -4671,6 +4671,9 @@ static void temp_load(TCGContext *s, TCGTemp *ts, TCGRegSet desired_regs,
         ts->mem_coherent = 0;
         break;
     case TEMP_VAL_MEM:
+        if (!ts->mem_allocated) {
+            temp_allocate_frame(s, ts);
+        }
         reg = tcg_reg_alloc(s, desired_regs, allocated_regs,
                             preferred_regs, ts->indirect_base);
         tcg_out_ld(s, ts->type, reg, ts->mem_base->reg, ts->mem_offset);