[mips] Add preliminary support for the MIPS II target.

Summary:
This patch enables code generation for the MIPS II target. Pre-Mips32
targets don't have the MUL instruction, so we add the correspondent
pattern that uses the MULT/MFLO combination in order to retrieve the
product.

This is WIP as we don't support code generation for select nodes due to
the lack of conditional-move instructions.

Reviewers: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6150

llvm-svn: 221686

4 files changed, 194 insertions, 5 deletions

diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.td b/llvm/lib/Target/Mips/MipsInstrInfo.td
index c89da01a61c..93ea6f6e8e6 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.td
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.td
@@ -1653,6 +1653,12 @@ let AdditionalPredicates = [NotDSP] in {
                 (ADDiu GPR32:$src, imm:$imm)>;
 }
 
+// Support multiplication for pre-Mips32 targets that don't have
+// the MUL instruction.
+def : MipsPat<(mul GPR32:$lhs, GPR32:$rhs),
+              (PseudoMFLO (PseudoMULT GPR32:$lhs, GPR32:$rhs))>,
+      ISA_MIPS1_NOT_32R6_64R6;
+
 // SYNC
 def : MipsPat<(MipsSync (i32 immz)),
               (SYNC 0)>, ISA_MIPS2;
diff --git a/llvm/lib/Target/Mips/MipsSubtarget.cpp b/llvm/lib/Target/Mips/MipsSubtarget.cpp
index ab8c03a1c50..8768b12f7d1 100644
--- a/llvm/lib/Target/Mips/MipsSubtarget.cpp
+++ b/llvm/lib/Target/Mips/MipsSubtarget.cpp
@@ -109,7 +109,7 @@ static std::string computeDataLayout(const MipsSubtarget &ST) {
 MipsSubtarget::MipsSubtarget(const std::string &TT, const std::string &CPU,
                              const std::string &FS, bool little,
                              const MipsTargetMachine *_TM)
-    : MipsGenSubtargetInfo(TT, CPU, FS), MipsArchVersion(Mips32),
+    : MipsGenSubtargetInfo(TT, CPU, FS), MipsArchVersion(MipsDefault),
       ABI(MipsABIInfo::Unknown()), IsLittle(little), IsSingleFloat(false),
       IsFPXX(false), NoABICalls(false), IsFP64bit(false), UseOddSPReg(true),
       IsNaN2008bit(false), IsGP64bit(false), HasVFPU(false), HasCnMips(false),
@@ -126,13 +126,14 @@ MipsSubtarget::MipsSubtarget(const std::string &TT, const std::string &CPU,
 
   PreviousInMips16Mode = InMips16Mode;
 
-  // Don't even attempt to generate code for MIPS-I, MIPS-II, MIPS-III, and
-  // MIPS-V. They have not been tested and currently exist for the integrated
+  if (MipsArchVersion == MipsDefault)
+    MipsArchVersion = Mips32;
+
+  // Don't even attempt to generate code for MIPS-I, MIPS-III and MIPS-V.
+  // They have not been tested and currently exist for the integrated
   // assembler only.
   if (MipsArchVersion == Mips1)
     report_fatal_error("Code generation for MIPS-I is not implemented", false);
-  if (MipsArchVersion == Mips2)
-    report_fatal_error("Code generation for MIPS-II is not implemented", false);
   if (MipsArchVersion == Mips3)
     report_fatal_error("Code generation for MIPS-III is not implemented",
                        false);
diff --git a/llvm/lib/Target/Mips/MipsSubtarget.h b/llvm/lib/Target/Mips/MipsSubtarget.h
index 1c37b84940e..bff90135f9c 100644
--- a/llvm/lib/Target/Mips/MipsSubtarget.h
+++ b/llvm/lib/Target/Mips/MipsSubtarget.h
@@ -37,6 +37,7 @@ class MipsSubtarget : public MipsGenSubtargetInfo {
   virtual void anchor();
 
   enum MipsArchEnum {
+    MipsDefault,
     Mips1, Mips2, Mips32, Mips32r2, Mips32r6, Mips3, Mips4, Mips5, Mips64,
     Mips64r2, Mips64r6
   };
diff --git a/llvm/test/CodeGen/Mips/llvm-ir/mul.ll b/llvm/test/CodeGen/Mips/llvm-ir/mul.ll
new file mode 100644
index 00000000000..167412407cd
--- /dev/null
+++ b/llvm/test/CodeGen/Mips/llvm-ir/mul.ll
@@ -0,0 +1,181 @@
+; RUN: llc < %s -march=mips -mcpu=mips2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=M2
+; RUN: llc < %s -march=mips -mcpu=mips32 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=32R1-R2 -check-prefix=32R1
+; RUN: llc < %s -march=mips -mcpu=mips32r2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=32R1-R2 -check-prefix=32R2
+; RUN: llc < %s -march=mips -mcpu=mips32r6 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=32R6
+; RUN: llc < %s -march=mips64 -mcpu=mips4 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=M4
+; RUN: llc < %s -march=mips64 -mcpu=mips64 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=64R1-R2
+; RUN: llc < %s -march=mips64 -mcpu=mips64r2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=64R1-R2
+; RUN: llc < %s -march=mips64 -mcpu=mips64r6 | FileCheck %s \
+; RUN:     -check-prefix=ALL -check-prefix=64R6
+
+define signext i1 @mul_i1(i1 signext %a, i1 signext %b) {
+entry:
+; ALL-LABEL: mul_i1:
+
+  ; M2:         mult    $4, $5
+  ; M2:         mflo    $[[T0:[0-9]+]]
+  ; M2:         sll     $[[T0]], $[[T0]], 31
+  ; M2:         sra     $2, $[[T0]], 31
+
+  ; 32R1-R2:    mul     $[[T0:[0-9]+]], $4, $5
+  ; 32R1-R2:    sll     $[[T0]], $[[T0]], 31
+  ; 32R1-R2:    sra     $2, $[[T0]], 31
+
+  ; 32R6:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 32R6:       sll     $[[T0]], $[[T0]], 31
+  ; 32R6:       sra     $2, $[[T0]], 31
+
+  ; M4:         mult    $4, $5
+  ; M4:         mflo    $[[T0:[0-9]+]]
+  ; M4:         sll     $[[T0]], $[[T0]], 31
+  ; M4:         sra     $2, $[[T0]], 31
+
+  ; 64R1-R2:    mul     $[[T0:[0-9]+]], $4, $5
+  ; 64R1-R2:    sll     $[[T0]], $[[T0]], 31
+  ; 64R1-R2:    sra     $2, $[[T0]], 31
+
+  ; 64R6:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 64R6:       sll     $[[T0]], $[[T0]], 31
+  ; 64R6:       sra     $2, $[[T0]], 31
+
+  %r = mul i1 %a, %b
+  ret i1 %r
+}
+
+define signext i8 @mul_i8(i8 signext %a, i8 signext %b) {
+entry:
+; ALL-LABEL: mul_i8:
+
+  ; M2:         mult    $4, $5
+  ; M2:         mflo    $[[T0:[0-9]+]]
+  ; M2:         sll     $[[T0]], $[[T0]], 24
+  ; M2:         sra     $2, $[[T0]], 24
+
+  ; 32R1:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 32R1:       sll     $[[T0]], $[[T0]], 24
+  ; 32R1:       sra     $2, $[[T0]], 24
+
+  ; 32R2:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 32R2:       seb     $2, $[[T0]]
+
+  ; 32R6:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 32R6:       seb     $2, $[[T0]]
+
+  ; M4:         mult    $4, $5
+  ; M4:         mflo    $[[T0:[0-9]+]]
+  ; M4:         sll     $[[T0]], $[[T0]], 24
+  ; M4:         sra     $2, $[[T0]], 24
+
+  ; 64R1:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 64R1:       sll     $[[T0]], $[[T0]], 24
+  ; 64R1:       sra     $2, $[[T0]], 24
+
+  ; 64R2:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 64R2:       seb     $2, $[[T0]]
+
+  ; 64R6:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 64R6:       seb     $2, $[[T0]]
+  %r = mul i8 %a, %b
+  ret i8 %r
+}
+
+define signext i16 @mul_i16(i16 signext %a, i16 signext %b) {
+entry:
+; ALL-LABEL: mul_i16:
+
+  ; M2:         mult    $4, $5
+  ; M2:         mflo    $[[T0:[0-9]+]]
+  ; M2:         sll     $[[T0]], $[[T0]], 16
+  ; M2:         sra     $2, $[[T0]], 16
+
+  ; 32R1:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 32R1:       sll     $[[T0]], $[[T0]], 16
+  ; 32R1:       sra     $2, $[[T0]], 16
+
+  ; 32R2:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 32R2:       seh     $2, $[[T0]]
+
+  ; 32R6:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 32R6:       seh     $2, $[[T0]]
+
+  ; M4:         mult    $4, $5
+  ; M4:         mflo    $[[T0:[0-9]+]]
+  ; M4:         sll     $[[T0]], $[[T0]], 16
+  ; M4:         sra     $2, $[[T0]], 16
+
+  ; 64R1:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 64R1:       sll     $[[T0]], $[[T0]], 16
+  ; 64R1:       sra     $2, $[[T0]], 16
+
+  ; 64R2:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 64R2:       seh     $2, $[[T0]]
+
+  ; 64R6:       mul     $[[T0:[0-9]+]], $4, $5
+  ; 64R6:       seh     $2, $[[T0]]
+  %r = mul i16 %a, %b
+  ret i16 %r
+}
+
+define signext i32 @mul_i32(i32 signext %a, i32 signext %b) {
+entry:
+; ALL-LABEL: mul_i32:
+
+  ; M2:         mult    $4, $5
+  ; M2:         mflo    $2
+
+  ; 32R1-R2:    mul     $2, $4, $5
+  ; 32R6:       mul     $2, $4, $5
+
+  ; 64R1-R2:    mul     $2, $4, $5
+  ; 64R6:       mul     $2, $4, $5
+  %r = mul i32 %a, %b
+  ret i32 %r
+}
+
+define signext i64 @mul_i64(i64 signext %a, i64 signext %b) {
+entry:
+; ALL-LABEL: mul_i64:
+
+  ; M2:         mult    $4, $7
+  ; M2:         mflo    $[[T0:[0-9]+]]
+  ; M2:         mult    $5, $6
+  ; M2:         mflo    $[[T1:[0-9]+]]
+  ; M2:         multu   $5, $7
+  ; M2:         mflo    $3
+  ; M2:         mfhi    $4
+  ; M2:         addu    $[[T2:[0-9]+]], $4, $[[T1]]
+  ; M2:         addu    $2, $[[T2]], $[[T0]]
+
+  ; 32R1-R2:    multu   $5, $7
+  ; 32R1-R2:    mflo    $3
+  ; 32R1-R2:    mfhi    $[[T0:[0-9]+]]
+  ; 32R1-R2:    mul     $[[T1:[0-9]+]], $4, $7
+  ; 32R1-R2:    mul     $[[T2:[0-9]+]], $5, $6
+  ; 32R1-R2:    addu    $[[T0]], $[[T0]], $[[T2:[0-9]+]]
+  ; 32R1-R2:    addu    $2, $[[T0]], $[[T1]]
+
+  ; 32R6:       mul     $[[T0:[0-9]+]], $5, $6
+  ; 32R6:       muhu    $[[T1:[0-9]+]], $5, $7
+  ; 32R6:       addu    $[[T0]], $[[T1]], $[[T0]]
+  ; 32R6:       mul     $[[T2:[0-9]+]], $4, $7
+  ; 32R6:       addu    $2, $[[T0]], $[[T2]]
+  ; 32R6:       mul     $3, $5, $7
+
+  ; M4:         dmult   $4, $5
+  ; M4:         mflo    $2
+
+  ; 64R1-R2:    dmult   $4, $5
+  ; 64R1-R2:    mflo    $2
+
+  ; 64R6:       dmul    $2, $4, $5
+
+  %r = mul i64 %a, %b
+  ret i64 %r
+}