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Re: Proposed doc update for Explicit Reg Vars 2/3


On 10/20/2015 03:12 AM, Segher Boessenkool wrote:
On Mon, Oct 19, 2015 at 11:14:30PM -0600, Jeff Law wrote:
+All global register variable declarations must precede all function
+definitions.  If such a declaration appears after function definitions,
+the declaration would be too late to prevent the register from being used
+for other purposes in the preceding functions.

This isn't true anymore, not even with -fno-toplevel-reorder or -O0.
I've asked David to verify this.  However, if you have, then he doesn't
need to re-confirm.

- - -
int f(int a, int b) { int t = a + b; return t*t + a + b; }
register int nope asm("9");
- - -

on PowerPC (GPR9 is the first one allocated, adjust for other archs).
Cool thanks. I figured this would be the case due to the nature of the IPA framework.

jeff


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