df47368d40
STATEPOINT is a fancy and complex pseudo instruction which has both tied defs and regmask operand. Basic FastRA algorithm is as follows: 1. Mark registers used by defs as free 2. If instruction has regmask operand displace clobbered registers according to regmask. 3. Assign registers for use operands. In case of tied defs step 1 is replaced with allocation of registers for them. But regmask is still processed, which may displace already allocated registers. As a result, tied use and def will get assigned to different registers. This patch makes FastRA to process instruction's RegMask (if any) when checking for physical registers interference. That way tied operands won't get registers clobbered by regmask. Reviewed By: arsenm, skatkov Differential Revision: https://reviews.llvm.org/D99284
41 lines
1.9 KiB
YAML
41 lines
1.9 KiB
YAML
# RUN: llc -mtriple=x86_64-- -run-pass=regallocfast -o - %s | FileCheck %s
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# Check that fastregalloc does not displace register assigned to tied def when
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# RegMask operand is present. STATEPOINT is an example of such instruction.
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# Tied def/use must be assigned to the same register.
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---
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name: test_relocate
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tracksRegLiveness: true
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body: |
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bb.0.entry:
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liveins: $rdi
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; CHECK: renamable [[REG:\$[a-z0-9]+]] = STATEPOINT 0, 0, 0, target-flags(x86-plt) 0, 2, 0, 2, 0, 2, 0, 2, 1, renamable [[REG]](tied-def 0)
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%1:gr64 = COPY $rdi
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ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
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%1:gr64 = STATEPOINT 0, 0, 0, target-flags(x86-plt) 0, 2, 0, 2, 0, 2, 0, 2, 1, %1(tied-def 0), 2, 0, 2, 1, 0, 0, csr_64, implicit-def $rsp, implicit-def $ssp
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ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
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$rax = COPY %1
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RET 0, killed $rax
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...
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# Same as above but with multiple RegMask operands per instruction.
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# These regmasks have no real meaning and chosen to allow only single register to be assignable ($r12)
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---
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name: test_relocate_multi_regmasks
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tracksRegLiveness: true
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body: |
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bb.0.entry:
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liveins: $rdi
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; CHECK: renamable $r12 = STATEPOINT 0, 0, 0, target-flags(x86-plt) 0, 2, 0, 2, 0, 2, 0, 2, 1, renamable $r12(tied-def 0)
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%1:gr64 = COPY $rdi
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ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
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%1:gr64 = STATEPOINT 0, 0, 0, target-flags(x86-plt) 0, 2, 0, 2, 0, 2, 0, 2, 1, %1(tied-def 0), 2, 0, 2, 1, 0, 0, csr_64_rt_allregs, csr_64_hhvm, implicit-def $rsp, implicit-def $ssp
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ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
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$rax = COPY %1
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RET 0, killed $rax
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...
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