diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp --- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp +++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp @@ -4437,6 +4437,9 @@ MF.getRegInfo().constrainRegClass(SrcReg, &AArch64::GPR64RegClass); return nullptr; } + // Nothing can folded with copy from/to NZCV. + if (SrcReg == AArch64::NZCV || DstReg == AArch64::NZCV) + return nullptr; } // Handle the case where a copy is being spilled or filled but the source diff --git a/llvm/test/CodeGen/AArch64/spill-fold.mir b/llvm/test/CodeGen/AArch64/spill-fold.mir --- a/llvm/test/CodeGen/AArch64/spill-fold.mir +++ b/llvm/test/CodeGen/AArch64/spill-fold.mir @@ -5,6 +5,7 @@ define i64 @test_subreg_spill_fold3() { ret i64 0 } define i64 @test_subreg_fill_fold() { ret i64 0 } define double @test_subreg_fill_fold2() { ret double 0.0 } + define i64 @test_nzcv_spill_fold() { ret i64 0 } ... --- # CHECK-LABEL: name: test_subreg_spill_fold @@ -80,3 +81,18 @@ $d0 = COPY %1 RET_ReallyLR implicit $d0 ... +--- +# CHECK-LABEL: name: test_nzcv_spill_fold +# Ensure that nzcv COPY cannot be folded. +name: test_nzcv_spill_fold +registers: + - { id: 0, class: gpr64 } +body: | + bb.0: + ; CHECK: %1:gpr64 = COPY $nzcv + ; CHECK: STRXui %1, %stack.0, 0 :: (store (s64) into %stack.0) + %0 = COPY $nzcv + INLINEASM &nop, 1, 12, implicit-def dead $x0, 12, implicit-def dead $x1, 12, implicit-def dead $x2, 12, implicit-def dead $x3, 12, implicit-def dead $x4, 12, implicit-def dead $x5, 12, implicit-def dead $x6, 12, implicit-def dead $x7, 12, implicit-def dead $x8, 12, implicit-def dead $x9, 12, implicit-def dead $x10, 12, implicit-def dead $x11, 12, implicit-def dead $x12, 12, implicit-def dead $x13, 12, implicit-def dead $x14, 12, implicit-def dead $x15, 12, implicit-def dead $x16, 12, implicit-def dead $x17, 12, implicit-def dead $x18, 12, implicit-def dead $x19, 12, implicit-def dead $x20, 12, implicit-def dead $x21, 12, implicit-def dead $x22, 12, implicit-def dead $x23, 12, implicit-def dead $x24, 12, implicit-def dead $x25, 12, implicit-def dead $x26, 12, implicit-def dead $x27, 12, implicit-def dead $x28, 12, implicit-def dead $fp, 12, implicit-def dead $lr, 12, implicit-def $sp + $x0 = COPY %0 + RET_ReallyLR implicit $x0 +...