e9a3ea2218
This PR instruments the optimization passes in the SystemZ backend with calls to `MachineFunction::substituteDebugValuesForInst` where instruction substitutions are made to instructions that may compute tracked values. Tests are also added for each of the substitutions that were inserted. Details on the individual passes follow. ### systemz-copy-physregs When a copy targets an access register, we redirect the copy via an auxiliary register. This leads to the final result being written by a newly inserted SAR instruction, rather than the original MI, so we need to update the debug value tracking to account for this. ### systemz-long-branch This pass relaxes relative branch instructions based on the actual locations of blocks. Only one of the branch instructions qualifies for debug value tracking: BRCT, i.e. branch-relative-on-count, which subtracts 1 from a register and branches if the result is not zero. This is relaxed into an add-immediate and a conditional branch, so any `debug-instr-number` present must move to the add-immediate instruction. ### systemz-post-rewrite This pass replaces `LOCRMux` and `SELRMux` pseudoinstructions with either the real versions of those instructions, or with branching programs that implement the intent of the Pseudo. In all these cases, any `debug-instr-number` attached to the pseudo needs to be reallocated to the appropriate instruction in the result, either LOCR, SELR, or a COPY. ### systemz-elim-compare Similar to systemz-long-branch, for this pass, only few substitutions are necessary, since it mainly deals with conditional branch instructions. The only exceptiona are again branch-relative-on-count, as it modifies a counter as part of the instruction, as well as any of the load instructions that are affected.
25 lines
1.2 KiB
YAML
25 lines
1.2 KiB
YAML
# Check that the backend properly tracks debug-instr-references across the
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# post-rewrite pass.
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#
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# RUN: llc %s -mtriple=s390x-linux-gnu -run-pass=systemz-post-rewrite \
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# RUN: -o - 2>&1 | FileCheck %s
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# SELRMux 1: simple replace with copy
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# SELRMux 2: simple mutation into selfhr
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# SELRMux 3: replace with if-then-else without prior copy
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# SELRMux 4: replace with if-then-else with prior copy
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# CHECK: name: foo
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# CHECK: debugValueSubstitutions:
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# CHECK-NEXT: - { srcinst: 1, srcop: 0, dstinst: 5, dstop: 0, subreg: 0 }
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# CHECK-NEXT: - { srcinst: 3, srcop: 0, dstinst: 6, dstop: 0, subreg: 0 }
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# CHECK-NEXT: - { srcinst: 4, srcop: 0, dstinst: 7, dstop: 0, subreg: 0 }
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# CHECK-NEXT: - { srcinst: 4, srcop: 0, dstinst: 8, dstop: 0, subreg: 0 }
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name: foo
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body: |
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bb.0:
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liveins: $r2h, $r3h, $r2l, $r3l, $cc
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SELRMux def $r2h, renamable $r3l, renamable $r3l, 1, 2, implicit $cc, debug-instr-number 1
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SELRMux def $r1h, renamable $r2h, renamable $r3h, 1, 2, implicit $cc, debug-instr-number 2
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SELRMux def $r2h, renamable $r2h, renamable $r3l, 1, 2, implicit $cc, debug-instr-number 3
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SELRMux def $r1h, renamable $r2l, renamable $r3l, 1, 2, implicit $cc, debug-instr-number 4
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