Commit 9087ef07 authored by Matt Arsenault's avatar Matt Arsenault Committed by Matt Arsenault
Browse files

GlobalISel: Allow CSE of G_IMPLICIT_DEF 

The legalizer produces a lot of these, and they make reading legalized
MIR annoying. For some reason, this does seem to sometimes introduce
copies of implicit def, which is dumb.
parent a4b590dd

llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp

+2 −1
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ bool CSEConfigFull::shouldCSEOpc(unsigned Opc) { 
  case TargetOpcode::G_SREM:

  case TargetOpcode::G_CONSTANT:

  case TargetOpcode::G_FCONSTANT:

  case TargetOpcode::G_IMPLICIT_DEF:

  case TargetOpcode::G_ZEXT:

  case TargetOpcode::G_SEXT:

  case TargetOpcode::G_ANYEXT:
@@ -64,7 +65,7 @@ bool CSEConfigFull::shouldCSEOpc(unsigned Opc) { 
}



bool CSEConfigConstantOnly::shouldCSEOpc(unsigned Opc) {

  return Opc == TargetOpcode::G_CONSTANT;

  return Opc == TargetOpcode::G_CONSTANT || Opc == TargetOpcode::G_IMPLICIT_DEF;

}



std::unique_ptr<CSEConfigBase>

llvm/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll

+1 −1
Original line number Diff line number Diff line
@@ -167,7 +167,7 @@ define void @nonpow2_load_narrowing() { 
  ret void

}



; FALLBACK-WITH-REPORT-ERR: remark: <unknown>:0:0: cannot select: %14:gpr64(s64), %15:gpr(s1) = G_UADDE %17:gpr, %17:gpr, %13:gpr (in function: nonpow2_store_narrowing)

; FALLBACK-WITH-REPORT-ERR: remark: <unknown>:0:0: cannot select: %{{[0-9]+}}:gpr64(s64), %{{[0-9]+}}:gpr(s1) = G_UADDE %{{[0-9]+}}:gpr, %{{[0-9]+}}:gpr, %{{[0-9]+}}:gpr (in function: nonpow2_store_narrowing)

; FALLBACK-WITH-REPORT-ERR: warning: Instruction selection used fallback path for nonpow2_store_narrowing

; FALLBACK-WITH-REPORT-OUT-LABEL: nonpow2_store_narrowing:

define void @nonpow2_store_narrowing(i96* %c) {

llvm/test/CodeGen/AArch64/GlobalISel/legalize-cmp.mir

+2 −3
Original line number Diff line number Diff line
@@ -47,11 +47,10 @@ body: | 
  ; CHECK: bb.0:

  ; CHECK:   successors: %bb.1(0x40000000), %bb.2(0x40000000)

  ; CHECK:   [[DEF:%[0-9]+]]:_(s64) = G_IMPLICIT_DEF

  ; CHECK:   [[DEF1:%[0-9]+]]:_(s64) = G_IMPLICIT_DEF

  ; CHECK:   [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 0

  ; CHECK:   [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 4294967296

  ; CHECK:   [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ult), [[DEF1]](s64), [[C1]]

  ; CHECK:   [[ICMP1:%[0-9]+]]:_(s32) = G_ICMP intpred(eq), [[DEF1]](s64), [[C1]]

  ; CHECK:   [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ult), [[DEF]](s64), [[C1]]

  ; CHECK:   [[ICMP1:%[0-9]+]]:_(s32) = G_ICMP intpred(eq), [[DEF]](s64), [[C1]]

  ; CHECK:   [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP1]](s32)

  ; CHECK:   [[ICMP2:%[0-9]+]]:_(s32) = G_ICMP intpred(ult), [[DEF]](s64), [[C]]

  ; CHECK:   [[COPY:%[0-9]+]]:_(s32) = COPY [[ICMP2]](s32)

llvm/test/CodeGen/AArch64/GlobalISel/legalize-phi.mir

+1 −2
Original line number Diff line number Diff line
@@ -618,11 +618,10 @@ body: | 
  ; CHECK:   [[COPY:%[0-9]+]]:_(s64) = COPY $x0

  ; CHECK:   [[COPY1:%[0-9]+]]:_(p0) = COPY $x1

  ; CHECK:   [[DEF:%[0-9]+]]:_(s64) = G_IMPLICIT_DEF

  ; CHECK:   [[DEF1:%[0-9]+]]:_(s64) = G_IMPLICIT_DEF

  ; CHECK:   G_BR %bb.1

  ; CHECK: bb.1:

  ; CHECK:   [[PHI:%[0-9]+]]:_(s64) = G_PHI [[DEF]](s64), %bb.0

  ; CHECK:   [[PHI1:%[0-9]+]]:_(s64) = G_PHI [[DEF1]](s64), %bb.0

  ; CHECK:   [[PHI1:%[0-9]+]]:_(s64) = G_PHI [[DEF]](s64), %bb.0

  ; CHECK:   [[PHI2:%[0-9]+]]:_(s64) = G_PHI [[COPY]](s64), %bb.0

  ; CHECK:   [[MV:%[0-9]+]]:_(s128) = G_MERGE_VALUES [[PHI]](s64), [[PHI1]](s64)

  ; CHECK:   G_STORE [[MV]](s128), [[COPY1]](p0) :: (store 16)

llvm/test/CodeGen/AArch64/GlobalISel/legalize-undef.mir

+3 −4
Original line number Diff line number Diff line
@@ -8,8 +8,7 @@ body: | 


    ; CHECK-LABEL: name: test_implicit_def

    ; CHECK: [[DEF:%[0-9]+]]:_(s64) = G_IMPLICIT_DEF

    ; CHECK: [[DEF1:%[0-9]+]]:_(s64) = G_IMPLICIT_DEF

    ; CHECK: [[MV:%[0-9]+]]:_(s128) = G_MERGE_VALUES [[DEF]](s64), [[DEF1]](s64)

    ; CHECK: [[MV:%[0-9]+]]:_(s128) = G_MERGE_VALUES [[DEF]](s64), [[DEF]](s64)

    ; CHECK: [[TRUNC:%[0-9]+]]:_(s64) = G_TRUNC [[MV]](s128)

    ; CHECK: $x0 = COPY [[TRUNC]](s64)

    %0:_(s128) = G_IMPLICIT_DEF
@@ -59,9 +58,9 @@ body: | 


    ; CHECK-LABEL: name: test_implicit_def_v4s64

    ; CHECK: [[DEF:%[0-9]+]]:_(<2 x s64>) = G_IMPLICIT_DEF

    ; CHECK: [[DEF1:%[0-9]+]]:_(<2 x s64>) = G_IMPLICIT_DEF

    ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s64>) = COPY [[DEF]](<2 x s64>)

    ; CHECK: $q0 = COPY [[DEF]](<2 x s64>)

    ; CHECK: $q1 = COPY [[DEF1]](<2 x s64>)

    ; CHECK: $q1 = COPY [[COPY]](<2 x s64>)

    %0:_(<4 x s64>) = G_IMPLICIT_DEF

    %1:_(<2 x s64> ), %2:_(<2 x s64>) = G_UNMERGE_VALUES %0

    $q0 = COPY %1