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i965/vs: Preserve the type when copy propagating into an instruction.
Consider the following code, which reinterprets a register as a
different type:
mov(8) g6<1>F g1.4<0,4,1>.xF
and(8) g5<1>.xUD g6<4,4,1>.xUD 0x7fffffffUD
Copy propagation would notice that we can replace the use of g6 with
g1.4 and eliminate the MOV. Unfortunately, it failed to preserve the UD
type, incorrectly generating:
and(8) g5<1>.xUD g6<4,4,1>.xF 0x7fffffffUD
Found while debugging Ian's uncommitted ARB_vertex_program LOG opcode
test with my new Mesa IR -> Vec4 IR translator.
NOTE: This is a candidate for stable release branches.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>