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Re: [PATCH 1/2] Allow REG_EQUAL for ZERO_EXTRACT



On 27/07/15 05:38, Andreas Schwab wrote:
> Kugan <kugan.vivekanandarajah@linaro.org> writes:
> 
>> 	* cse.c (cse_insn): Fix missing check for STRICT_LOW_PART and minor
>> 	clean up.
> 
> This breaks 
> 
> gcc.target/m68k/tls-ie-xgot.c scan-assembler jsr __m68k_read_tp
> gcc.target/m68k/tls-ie.c scan-assembler jsr __m68k_read_tp
> gcc.target/m68k/tls-le-xtls.c scan-assembler jsr __m68k_read_tp
> gcc.target/m68k/tls-le.c scan-assembler jsr __m68k_read_tp
> 
> Andreas.
> 

Sorry for the breakage. My patch to add ZERO_EXTRACT unfortunately
restricts the behaviour in one other case. That is, even when REG_EQUAL
note and src are same, we were setting src_eqv to src when it is
STRICT_LOW_PART. Not sure why but restored the old behaviour.

I could reproduce this issue by inspecting the generated asm and made
sure that it is fixed. However I could not run regression for m68k
(Sorry I don’t have access to the set-up).
I bootstrapped and regression tested on x86_64-linux-gnu and
arm-none-linux-gnu with no new regressions.

Thanks,
Kugan


gcc/ChangeLog:

2015-07-27  Kugan Vivekanandarajah  <kuganv@linaro.org>

	* cse.c (cse_insn): Restoring old behaviour for src_eqv
	 when dest and value in the REG_EQUAL are same and dest
	 is STRICT_LOW_PART.

Attachment: p.txt
Description: Text document


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