[MIPS] [microMIPS] Fix PseudoMTLOHI_MM matching and expansion

[mbrkusanin]

Summary

On micromips MipsMTLOHI is always matched to PseudoMTLOHI_DSP regardless of
+dsp argument. This patch checks is HasDSP predicate is present for
PseudoMTLOHI_DSP so PseudoMTLOHI_MM can be matched when appropriate.

Add expansion of PseudoMTLOHI_MM instruction into a mtlo/mthi pair.

[atanasyan]

I think we can join D59203 and D59204 patches. Now LLVM incorrectly generates dsp instructions in all cases. After applying D59203 it starts to use PseudoMTLOHI_MM, but test case from the D59204 crashes llc. And after applying the D59204 everything work okay. Let's do an atomic change.

[mbrkusanin]

Combined with it's child revision D59204.

[atanasyan]

We can drop micromips-pseudo-mtlohi-match.ll and keep the micromips-pseudo-mtlohi-expand.ll only because this test checks all that is necessary. With this modification the patch is LGTM.

[mbrkusanin]

Removed micromips-pseudo-mtlohi-match.ll

[mbrkusanin]

Removed micromips 32r6 RUN: line. MTHI and MTLO were removed from micromips R6 so this test is unnecessary.

llvm/trunk/lib/Target/Mips/MipsDSPInstrInfo.td

 def PseudoCMP_LE_PH : PseudoCMP<CMP_LE_PH>;
 def PseudoCMPU_EQ_QB : PseudoCMP<CMPU_EQ_QB>;
 def PseudoCMPU_LT_QB : PseudoCMP<CMPU_LT_QB>;
 def PseudoCMPU_LE_QB : PseudoCMP<CMPU_LE_QB>;
 
 def PseudoPICK_PH : PseudoPICK<PICK_PH>;
 def PseudoPICK_QB : PseudoPICK<PICK_QB>;
 
+let AdditionalPredicates = [HasDSP] in {
   def PseudoMTLOHI_DSP : PseudoMTLOHI<ACC64DSP, GPR32>;
+}
 
 // Patterns.
 class DSPPat<dag pattern, dag result, Predicate pred = HasDSP> :
   Pat<pattern, result>, Requires<[pred]>;
 
 class BitconvertPat<ValueType DstVT, ValueType SrcVT, RegisterClass DstRC,
                     RegisterClass SrcRC> :
    DSPPat<(DstVT (bitconvert (SrcVT SrcRC:$src))),

llvm/trunk/lib/Target/Mips/MipsSEInstrInfo.cpp

case Mips::PseudoMTLOHI:
     expandPseudoMTLoHi(MBB, MI, Mips::MTLO, Mips::MTHI, false);
     break;
   case Mips::PseudoMTLOHI64:
     expandPseudoMTLoHi(MBB, MI, Mips::MTLO64, Mips::MTHI64, false);
     break;
   case Mips::PseudoMTLOHI_DSP:
     expandPseudoMTLoHi(MBB, MI, Mips::MTLO_DSP, Mips::MTHI_DSP, true);
     break;
+  case Mips::PseudoMTLOHI_MM:
+    expandPseudoMTLoHi(MBB, MI, Mips::MTLO_MM, Mips::MTHI_MM, false);
+    break;
   case Mips::PseudoCVT_S_W:
     expandCvtFPInt(MBB, MI, Mips::CVT_S_W, Mips::MTC1, false);
     break;
   case Mips::PseudoCVT_D32_W:
     Opc = isMicroMips ? Mips::CVT_D32_W_MM : Mips::CVT_D32_W;
     expandCvtFPInt(MBB, MI, Opc, Mips::MTC1, false);
     break;
   case Mips::PseudoCVT_S_L:

llvm/trunk/test/CodeGen/Mips/micromips-pseudo-mtlohi-expand.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=mipsel-linux-gnu -mcpu=mips32r2 -mattr=+micromips -asm-show-inst < %s |\
+; RUN:   FileCheck %s -check-prefixes=MMR2
+; RUN: llc -mtriple=mipsel-linux-gnu -mcpu=mips32r2 -mattr=+dsp,+micromips -asm-show-inst < %s |\
+; RUN:   FileCheck %s -check-prefixes=MMR2-DSP
+
+define i64 @test(i32 signext %a, i32 signext %b) {
+; MMR2-LABEL: test:
+; MMR2:       # %bb.0: # %entry
+; MMR2-NEXT:    li16 $2, 0 # <MCInst #1700 LI16_MM
+; MMR2-NEXT:    # <MCOperand Reg:321>
+; MMR2-NEXT:    # <MCOperand Imm:0>>
+; MMR2-NEXT:    li16 $3, 1 # <MCInst #1700 LI16_MM
+; MMR2-NEXT:    # <MCOperand Reg:322>
+; MMR2-NEXT:    # <MCOperand Imm:1>>
+; MMR2-NEXT:    mtlo $3 # <MCInst #2008 MTLO_MM
+; MMR2-NEXT:    # <MCOperand Reg:322>>
+; MMR2-NEXT:    mthi $2 # <MCInst #2001 MTHI_MM
+; MMR2-NEXT:    # <MCOperand Reg:321>>
+; MMR2-NEXT:    madd $4, $5 # <MCInst #1774 MADD
+; MMR2-NEXT:    # <MCOperand Reg:22>
+; MMR2-NEXT:    # <MCOperand Reg:23>>
+; MMR2-NEXT:    mflo16 $2 # <MCInst #1860 MFLO16_MM
+; MMR2-NEXT:    # <MCOperand Reg:321>>
+; MMR2-NEXT:    mfhi16 $3 # <MCInst #1854 MFHI16_MM
+; MMR2-NEXT:    # <MCOperand Reg:322>>
+; MMR2-NEXT:    jrc $ra # <MCInst #1632 JRC16_MM
+; MMR2-NEXT:    # <MCOperand Reg:19>>
+;
+; MMR2-DSP-LABEL: test:
+; MMR2-DSP:       # %bb.0: # %entry
+; MMR2-DSP-NEXT:    li16 $2, 0 # <MCInst #1700 LI16_MM
+; MMR2-DSP-NEXT:    # <MCOperand Reg:321>
+; MMR2-DSP-NEXT:    # <MCOperand Imm:0>>
+; MMR2-DSP-NEXT:    li16 $3, 1 # <MCInst #1700 LI16_MM
+; MMR2-DSP-NEXT:    # <MCOperand Reg:322>
+; MMR2-DSP-NEXT:    # <MCOperand Imm:1>>
+; MMR2-DSP-NEXT:    mtlo $3, $ac0 # <MCInst #2006 MTLO_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:291>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:322>>
+; MMR2-DSP-NEXT:    mthi $2, $ac0 # <MCInst #1999 MTHI_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:253>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:321>>
+; MMR2-DSP-NEXT:    madd $ac0, $4, $5 # <MCInst #1792 MADD_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:26>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:22>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:23>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:26>>
+; MMR2-DSP-NEXT:    mflo $2, $ac0 # <MCInst #1862 MFLO_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:321>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:26>>
+; MMR2-DSP-NEXT:    jr $ra # <MCInst #1639 JR_MM
+; MMR2-DSP-NEXT:    # <MCOperand Reg:19>>
+; MMR2-DSP-NEXT:    mfhi $3, $ac0 # <MCInst #1856 MFHI_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:322>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:26>>
+entry:
+  %conv = sext i32 %a to i64
+  %conv1 = sext i32 %b to i64
+  %mul = mul nsw i64 %conv, %conv1
+  %add = add nsw i64 %mul, 1
+  ret i64 %add
+}