This rewrites big parts of the fast register allocator. The basic
strategy of doing block-local allocation hasn't changed but I tweaked
several details:
Track register state on register units instead of physical
registers. This simplifies and speeds up handling of register aliases.
Process basic blocks in reverse order: Definitions are known to end
register livetimes when walking backwards (contrary when walking
forward then uses may or may not be a kill so we need heuristics).
Check register mask operands (calls) instead of conservatively
assuming everything is clobbered. Enhance heuristics to detect
killing uses: In case of a small number of defs/uses check if they are
all in the same basic block and if so the last one is a killing use.
Enhance heuristic for copy-coalescing through hinting: We check the
first k defs of a register for COPYs rather than relying on there just
being a single definition. When testing this on the full llvm
test-suite including SPEC externals I measured:
average 5.1% reduction in code size for X86, 4.9% reduction in code on
aarch64. (ranging between 0% and 20% depending on the test) 0.5%
faster compiletime (some analysis suggests the pass is slightly slower
than before, but we more than make up for it because later passes are
faster with the reduced instruction count)
Also adds a few testcases that were broken without this patch, in
particular bug 47278.
Patch mostly by Matthias Braun
Introduce IntImmLeaf version of PatLeaf immZExt16 for 32-bit immediates.
Change immZExt16 with imm32ZExt16 for andi, ori and xori.
This keeps same behavior for SDAG and allows for GlobalISel selectImpl
to select 'G_CONSTANT imm' + G_AND, G_OR, G_XOR into ANDi, ORi, XORi,
respectively, when 32-bit imm satisfies imm32ZExt16 predicate: zero
extending 16 low bits of imm is equal to imm.
Large number of test changes comes from zero extending of small types
which is transformed into 'and' with bitmask in legalizer.
Differential Revision:https://reviews.llvm.org/D70185
This is a special case because one node maps to two different G_
instructions, and the operand order is changed.
This mostly enables G_FCMP for AMDPGPU. G_ICMP is still manually
selected for now since it has the SALU and VALU complication to deal
with.
llvm-svn: 370280
Add narrowScalar for G_AND and G_XOR.
Legalize G_AND G_OR and G_XOR for types other then s32
with clampScalar on MIPS32.
Differential Revision: https://reviews.llvm.org/D55362
llvm-svn: 349475
Matt Arsenault