[Hexagon] Do not insert non-phis before phis in bit simplification

llvm-svn: 257606

llvm/lib/Target/Hexagon/HexagonBitSimplify.cpp

@@ -1275,6 +1275,8 @@ bool RedundantInstrElimination::processBlock(MachineBasicBlock &B,
     if (!BT.has(RD.Reg))
       continue;
     const BitTracker::RegisterCell &DC = BT.lookup(RD.Reg);
+    auto At = MI->isPHI() ? B.getFirstNonPHI()
+                          : MachineBasicBlock::iterator(MI);
 
     // Find a source operand that is equal to the result.
     for (auto &Op : MI->uses()) {
@@ -1298,7 +1300,7 @@ bool RedundantInstrElimination::processBlock(MachineBasicBlock &B,
       DebugLoc DL = MI->getDebugLoc();
       const TargetRegisterClass *FRC = HBS::getFinalVRegClass(RD, MRI);
       unsigned NewR = MRI.createVirtualRegister(FRC);
-      BuildMI(B, I, DL, HII.get(TargetOpcode::COPY), NewR)
+      BuildMI(B, At, DL, HII.get(TargetOpcode::COPY), NewR)
           .addReg(RS.Reg, 0, RS.Sub);
       HBS::replaceSubWithSub(RD.Reg, RD.Sub, NewR, 0, MRI);
       BT.put(BitTracker::RegisterRef(NewR), SC);
@@ -1925,7 +1927,9 @@ bool BitSimplification::genPackhl(MachineInstr *MI,
   MachineBasicBlock &B = *MI->getParent();
   unsigned NewR = MRI.createVirtualRegister(&Hexagon::DoubleRegsRegClass);
   DebugLoc DL = MI->getDebugLoc();
-  BuildMI(B, MI, DL, HII.get(Hexagon::S2_packhl), NewR)
+  auto At = MI->isPHI() ? B.getFirstNonPHI()
+                        : MachineBasicBlock::iterator(MI);
+  BuildMI(B, At, DL, HII.get(Hexagon::S2_packhl), NewR)
       .addReg(Rs.Reg, 0, Rs.Sub)
       .addReg(Rt.Reg, 0, Rt.Sub);
   HBS::replaceSubWithSub(RD.Reg, RD.Sub, NewR, 0, MRI);
@@ -1950,9 +1954,11 @@ bool BitSimplification::genExtractHalf(MachineInstr *MI,
   // Prefer zxth, since zxth can go in any slot, while extractu only in
   // slots 2 and 3.
   unsigned NewR = 0;
+  auto At = MI->isPHI() ? B.getFirstNonPHI()
+                        : MachineBasicBlock::iterator(MI);
   if (L.Low && Opc != Hexagon::A2_zxth) {
     NewR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass);
-    BuildMI(B, MI, DL, HII.get(Hexagon::A2_zxth), NewR)
+    BuildMI(B, At, DL, HII.get(Hexagon::A2_zxth), NewR)
         .addReg(L.Reg, 0, L.Sub);
   } else if (!L.Low && Opc != Hexagon::S2_extractu) {
     NewR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass);
@@ -1989,7 +1995,9 @@ bool BitSimplification::genCombineHalf(MachineInstr *MI,
   MachineBasicBlock &B = *MI->getParent();
   DebugLoc DL = MI->getDebugLoc();
   unsigned NewR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass);
-  BuildMI(B, MI, DL, HII.get(COpc), NewR)
+  auto At = MI->isPHI() ? B.getFirstNonPHI()
+                        : MachineBasicBlock::iterator(MI);
+  BuildMI(B, At, DL, HII.get(COpc), NewR)
       .addReg(H.Reg, 0, H.Sub)
       .addReg(L.Reg, 0, L.Sub);
   HBS::replaceSubWithSub(RD.Reg, RD.Sub, NewR, 0, MRI);
@@ -2043,7 +2051,9 @@ bool BitSimplification::genExtractLow(MachineInstr *MI,
       continue;
 
     unsigned NewR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass);
-    auto MIB = BuildMI(B, MI, DL, HII.get(NewOpc), NewR)
+    auto At = MI->isPHI() ? B.getFirstNonPHI()
+                          : MachineBasicBlock::iterator(MI);
+    auto MIB = BuildMI(B, At, DL, HII.get(NewOpc), NewR)
                   .addReg(RS.Reg, 0, RS.Sub);
     if (NewOpc == Hexagon::A2_andir)
       MIB.addImm((1 << W) - 1);
@@ -2076,6 +2086,8 @@ bool BitSimplification::simplifyTstbit(MachineInstr *MI,
   if (!BT.has(RS.Reg) || !HBS::getSubregMask(RS, F, W, MRI))
     return false;
   MachineBasicBlock &B = *MI->getParent();
+  auto At = MI->isPHI() ? B.getFirstNonPHI()
+                        : MachineBasicBlock::iterator(MI);
 
   const BitTracker::RegisterCell &SC = BT.lookup(RS.Reg);
   const BitTracker::BitValue &V = SC[F+BN];
@@ -2098,7 +2110,7 @@ bool BitSimplification::simplifyTstbit(MachineInstr *MI,
     }
     if (P != UINT_MAX) {
       unsigned NewR = MRI.createVirtualRegister(&Hexagon::PredRegsRegClass);
-      BuildMI(B, MI, DL, HII.get(Hexagon::S2_tstbit_i), NewR)
+      BuildMI(B, At, DL, HII.get(Hexagon::S2_tstbit_i), NewR)
           .addReg(RR.Reg, 0, RR.Sub)
           .addImm(P);
       HBS::replaceReg(RD.Reg, NewR, MRI);
@@ -2108,7 +2120,7 @@ bool BitSimplification::simplifyTstbit(MachineInstr *MI,
   } else if (V.is(0) || V.is(1)) {
     unsigned NewR = MRI.createVirtualRegister(&Hexagon::PredRegsRegClass);
     unsigned NewOpc = V.is(0) ? Hexagon::TFR_PdFalse : Hexagon::TFR_PdTrue;
-    BuildMI(B, MI, DL, HII.get(NewOpc), NewR);
+    BuildMI(B, At, DL, HII.get(NewOpc), NewR);
     HBS::replaceReg(RD.Reg, NewR, MRI);
     return true;
   }

llvm/test/CodeGen/Hexagon/bit-phi.ll

@@ -0,0 +1,58 @@
+; RUN: llc -march=hexagon < %s
+; REQUIRES: asserts
+
+target datalayout = "e-m:e-p:32:32-i1:32-i64:64-a:0-v32:32-n16:32"
+target triple = "hexagon-unknown--elf"
+
+%struct.item = type { i32, i8*, i8*, i32, i8, i8, i16, i32, i8, i16, i32 }
+
+declare %struct.item* @foo(%struct.item*, i8*, i32) #1
+
+; Function Attrs: nounwind
+define i32 @bar(%struct.item** %ptr, i8* %buf, i32 %c, i8* %d, i32 %e) #1 {
+entry:
+  br i1 undef, label %return, label %if.end
+
+if.end:                                           ; preds = %entry
+  br i1 undef, label %while.cond13.preheader, label %if.end3
+
+if.end3:                                          ; preds = %if.end
+  br label %while.cond13.preheader
+
+while.cond13.preheader:                           ; preds = %if.end3, %if.end
+  br i1 undef, label %while.body20, label %return
+
+while.body20:                                     ; preds = %if.end38, %while.cond13.preheader
+  %addr.0100 = phi i32 [ undef, %if.end38 ], [ %c, %while.cond13.preheader ]
+  %cond = select i1 undef, i32 %addr.0100, i32 undef
+  br i1 undef, label %while.body20.if.end38_crit_edge, label %if.then32
+
+while.body20.if.end38_crit_edge:                  ; preds = %while.body20
+  %conv39.pre = and i32 %cond, 65535
+  br label %if.end38
+
+if.then32:                                        ; preds = %while.body20
+  %conv33 = and i32 %cond, 65535
+  %.pre = load %struct.item*, %struct.item** %ptr, align 4, !tbaa !1
+  br label %if.end38
+
+if.end38:                                         ; preds = %if.then32, %while.body20.if.end38_crit_edge
+  %conv39.pre-phi = phi i32 [ %conv39.pre, %while.body20.if.end38_crit_edge ], [ %conv33, %if.then32 ]
+  %0 = phi %struct.item* [ undef, %while.body20.if.end38_crit_edge ], [ %.pre, %if.then32 ]
+  %add = add i32 %conv39.pre-phi, 0
+  %call52 = tail call %struct.item* @foo(%struct.item* %0, i8* %d, i32 %e) #1
+  br i1 undef, label %while.body20, label %return
+
+return:                                           ; preds = %if.end38, %while.cond13.preheader, %entry
+  %retval.0 = phi i32 [ 0, %entry ], [ 0, %while.cond13.preheader ], [ %add, %if.end38 ]
+  ret i32 %retval.0
+}
+
+
+attributes #0 = { nounwind readonly }
+attributes #1 = { nounwind }
+
+!1 = !{!2, !2, i64 0}
+!2 = !{!"any pointer", !3, i64 0}
+!3 = !{!"omnipotent char", !4, i64 0}
+!4 = !{!"Simple C/C++ TBAA"}