llvm-project/llvm/test/CodeGen/AArch64/flags-multiuse.ll

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; RUN: llc -mtriple=aarch64-none-linux-gnu -aarch64-enable-atomic-cfg-tidy=0 -verify-machineinstrs -o - %s | FileCheck %s
; LLVM should be able to cope with multiple uses of the same flag-setting
; instruction at different points of a routine. Either by rematerializing the
; compare or by saving and restoring the flag register.
declare void @bar()
@var = global i32 0
define i32 @test_multiflag(i32 %n, i32 %m, i32 %o) {
; CHECK-LABEL: test_multiflag:
%test = icmp ne i32 %n, %m
; CHECK: cmp [[LHS:w[0-9]+]], [[RHS:w[0-9]+]]
%val = zext i1 %test to i32
; CHECK: cset {{[xw][0-9]+}}, ne
Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding" Issues addressed since original review: - Avoid bug in regalloc greedy/machine verifier when forwarding to use in an instruction that re-defines the same virtual register. - Fixed bug when forwarding to use in EarlyClobber instruction slot. - Fixed incorrect forwarding to register definitions that showed up in explicit_uses() iterator (e.g. in INLINEASM). - Moved removal of dead instructions found by LiveIntervals::shrinkToUses() outside of loop iterating over instructions to avoid instructions being deleted while pointed to by iterator. - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907. - The pass no longer forwards COPYs to physical register uses, since doing so can break code that implicitly relies on the physical register number of the use. - The pass no longer forwards COPYs to undef uses, since doing so can break the machine verifier by creating LiveRanges that don't end on a use (since the undef operand is not considered a use). [MachineCopyPropagation] Extend pass to do COPY source forwarding This change extends MachineCopyPropagation to do COPY source forwarding. This change also extends the MachineCopyPropagation pass to be able to be run during register allocation, after physical registers have been assigned, but before the virtual registers have been re-written, which allows it to remove virtual register COPY LiveIntervals that become dead through the forwarding of all of their uses. llvm-svn: 314729
2017-10-03 06:01:37 +08:00
; CHECK: mov [[RHSCOPY:w[0-9]+]], [[RHS]]
; CHECK: mov [[LHSCOPY:w[0-9]+]], [[LHS]]
store i32 %val, i32* @var
call void @bar()
; CHECK: bl bar
; Currently, the comparison is emitted again. An MSR/MRS pair would also be
; acceptable, but assuming the call preserves NZCV is not.
br i1 %test, label %iftrue, label %iffalse
Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding" Issues addressed since original review: - Avoid bug in regalloc greedy/machine verifier when forwarding to use in an instruction that re-defines the same virtual register. - Fixed bug when forwarding to use in EarlyClobber instruction slot. - Fixed incorrect forwarding to register definitions that showed up in explicit_uses() iterator (e.g. in INLINEASM). - Moved removal of dead instructions found by LiveIntervals::shrinkToUses() outside of loop iterating over instructions to avoid instructions being deleted while pointed to by iterator. - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907. - The pass no longer forwards COPYs to physical register uses, since doing so can break code that implicitly relies on the physical register number of the use. - The pass no longer forwards COPYs to undef uses, since doing so can break the machine verifier by creating LiveRanges that don't end on a use (since the undef operand is not considered a use). [MachineCopyPropagation] Extend pass to do COPY source forwarding This change extends MachineCopyPropagation to do COPY source forwarding. This change also extends the MachineCopyPropagation pass to be able to be run during register allocation, after physical registers have been assigned, but before the virtual registers have been re-written, which allows it to remove virtual register COPY LiveIntervals that become dead through the forwarding of all of their uses. llvm-svn: 314729
2017-10-03 06:01:37 +08:00
; CHECK: cmp [[LHSCOPY]], [[RHSCOPY]]
; CHECK: b.eq
iftrue:
ret i32 42
iffalse:
ret i32 0
}