[cfe-dev] MS 128-bit literals don't always have the correct type

Aaron Ballman aaron at aaronballman.com
Mon Sep 24 06:15:17 PDT 2012

On Mon, Sep 24, 2012 at 12:46 AM, Richard Smith <richard at metafoo.co.uk> wrote:
> Incidentally, we currently treat (for instance) 1000000000000000000i32 as a
> 64-bit integer. How does MSVC behave here? (Does i32 mean "this shall be an
> int32_t", or does it mean "this shall be *at least* an int32_t"?)

It seems to mean that it shall be an int32_t.  In both 32- and 64-bit compiles.

// 32-bit
; 2    :   auto i = 1000000000000000000i32;
	mov	DWORD PTR _i$[ebp], -1486618624		; a7640000H

// 64-bit
; 2    :   auto i = 1000000000000000000i32;
	mov	DWORD PTR i$[rsp], -1486618624		; ffffffffa7640000H

However, I can't find documentation on MSDN to suggest that this is
intended behavior or not.  The only integer type suffix documentation
they have lists i64, ll and LL (plus the u variants), but not i32.



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