For an inexact-associative operation (fadd or fmul), can_reassociate ensures the
root of the chain is inexact to allow reassociating. However, build_chain just
checks for opcodes to match up after, although we do sum up exactness across the
chain. Although an Effort Was Made, it still seems incorrect to reassociate
%3 = fadd! %0, %1
%4 = fadd %3, %2
to instead be (ex.)
%3 = fadd! %0, %2
%4 = fadd! %3, %1
Closes: #14418
Fixes: e0b0f7e73c ("nir: add ALU reassocation pass")
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@intel.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
(cherry picked from commit 0c49738211)
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41269>
fb55d222fc