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r242182 - in /branches/ARM/sve-branch/gcc: asan...
- From: rsandifo at gcc dot gnu dot org
- To: gcc-cvs at gcc dot gnu dot org
- Date: Fri, 11 Nov 2016 17:14:19 -0000
- Subject: r242182 - in /branches/ARM/sve-branch/gcc: asan...
Date: Fri Nov 11 17:14:19 2016
New Revision: 242182
Add helpers for shift count modes
This patch adds a stub helper routine to provide the mode
of a scalar shift amount, given the mode of the values
One long-standing problem has been to decide what this mode
should be for arbitrary rtxes (as opposed to those directly
tied to a target pattern). Is it the mode of the shifted
elements? Is it word_mode? Or maybe QImode? Is it whatever
the corresponding target pattern says? (In which case what
should the mode be when the target doesn't have a pattern?)
For now the patch picks word_mode, which should be safe on
all targets but could perhaps become suboptimal if the helper
routine is used more often than it is in this patch.
The patch also adds a helper function that constructs rtxes
for constant shift amounts, again given the mode of the value
being shifted. As well as helping with the SVE patches, this
is one step towards allowing CONST_INTs to have a real mode.