Since GCC 8, the -freorder-blocks-and-partition pass can split a function into 
hot and cold parts, thus generating 2 FDEs for a single function in DWARF for 
exception purposes and doing an equivalent trick for Windows SEH on x86-64.

Now the Windows system unwinder does not support arbitrarily large frames and 
there is even a hard limit on the encoding of the CFI, which changes the stack 
allocation strategy when it is topped and which must be reflected everywhere.

I overlooked that when implementing the -freorder-blocks-and-partition support 
back in 2018 and this results in an ICE when gigantic frames, like e.g. in the 
attached Ada testcase.

Bootstrapped on x86-64/Windows, applied on all active branches as obvious.


2021-04-19  Eric Botcazou  <ebotcazou@adacore.com>

	* config/i386/winnt.c (i386_pe_seh_cold_init): Properly deal with
	frames larger than the SEH maximum frame size.


2021-04-19  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/opt92.adb: New test.

-- 
Eric Botcazou