Hi,
On Mon, Apr 13, 2020 at 10:24:39PM -0400, Michael Meissner wrote:
> This patch fixes PR target/94557, on PowerPC. It was a regression on the GCC
> 9
> branch caused by my recent patch for PR target/93932.
>
> The patch for 93932 was a back port from the master branch of a fix for the
> vec_extract built-in function. This patch fixes the case where we are
> optimizing a vector extract from an vector in memory to be a scalar load
> instead of loading the vector to a register and then doing an extract.
What does "this patch" mean? The backport?
> This patch adds in the masking of the vector index that is in the master
> branch. I re-implemented the change for GCC 9, since the changes on the
> master
> branch are more extensive, and include PC-relative support that is not in GCC
> 9.
Hrm.
> 2020-04-13 Michael Meissner <meiss...@linux.ibm.com>
>
> PR target/94557
> * config/rs6000/rs6000.c (rs6000_adjust_vec_address): Mask
> variable vector extract index so it does not go beyond the vector
> when extracting a vector element from memory. This change is a
> simplification of the 2020-02-03 patch that went into the trunk.
You have no patches go into trunk at that date.
> --- /tmp/4XFFqK_rs6000.c 2020-04-13 15:28:33.514011024 -0500
> +++ gcc/config/rs6000/rs6000.c 2020-04-13 14:24:01.296932921 -0500
> @@ -7047,18 +7047,25 @@ rs6000_adjust_vec_address (rtx scalar_re
> element_offset = GEN_INT (INTVAL (element) * scalar_size);
> else
> {
> + /* Mask the element to make sure the element number is between 0 and
> the
> + maximum number of elements - 1 so that we don't generate an address
> + outside the vector. */
The patch introducing this to trunk was reverted.
I don't get the warm and fuzzies from this patch. How can I expect that
it won't cause more problems than it solves, like this? Reverts and new
implementations, and also mislabeled?
Please explain this better?
Segher
