Files
clang-p2996/llvm/test/CodeGen/AArch64/flags-multiuse.ll
Quentin Colombet 48abac82b8 Revert "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
This reverts commit r323991.

This commit breaks target that don't model all the register constraints
in TableGen. So far the workaround was to set the
hasExtraXXXRegAllocReq, but it proves that it doesn't cover all the
cases.
For instance, when mutating an instruction (like in the lowering of
COPYs) the isRenamable flag is not properly updated. The same problem
will happen when attaching machine operand from one instruction to
another.

Geoff Berry is working on a fix in https://reviews.llvm.org/D43042.

llvm-svn: 325421
2018-02-17 03:05:33 +00:00

36 lines
937 B
LLVM

; 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
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
; CHECK: cmp [[LHS]], [[RHS]]
; CHECK: b.eq
iftrue:
ret i32 42
iffalse:
ret i32 0
}