mips-force-nomadd4

The MIPS port aims to support the Loongson 3 family of CPUs in addition
of the other MIPS CPUs. On the Loongson 3 family the MADD4 instructions
are fused, while they are not fused on the other MIPS CPUs. In order to
support both, we have to disabled those instructions.

For that, the patch below basically corresponds to the --with-madd4=no
used on the GCC side.

Gbp-Pq: Topic mips
Gbp-Pq: Name mips-force-nomadd4.patch

diff --git a/clang/lib/Basic/Targets/Mips.h b/clang/lib/Basic/Targets/Mips.h
index b54d36e1c95f2b74fc2023733e774dfa35aa549a..0c74508a813b38bfb0522022dce4a7d0054c250d 100644 (file)
--- a/clang/lib/Basic/Targets/Mips.h
+++ b/clang/lib/Basic/Targets/Mips.h
@@ -332,6 +332,8 @@ public:
         HasMSA = true;
       else if (Feature == "+nomadd4")
         DisableMadd4 = true;
+      else if (Feature == "-nomadd4")
+        DisableMadd4 = false;
       else if (Feature == "+fp64")
         FPMode = FP64;
       else if (Feature == "-fp64")

diff --git a/llvm/lib/Target/Mips/MipsSubtarget.cpp b/llvm/lib/Target/Mips/MipsSubtarget.cpp
index c285385a19dd36c499bb0b8f4a8a01c9cb4d3dff..6bf98cbc71d3ed2d0c14a0b0c89586fe9085e320 100644 (file)
--- a/llvm/lib/Target/Mips/MipsSubtarget.cpp
+++ b/llvm/lib/Target/Mips/MipsSubtarget.cpp
@@ -80,7 +80,7 @@ MipsSubtarget::MipsSubtarget(const Triple &TT, StringRef CPU, StringRef FS,
       InMips16HardFloat(Mips16HardFloat), InMicroMipsMode(false), HasDSP(false),
       HasDSPR2(false), HasDSPR3(false), AllowMixed16_32(Mixed16_32 || Mips_Os16),
       Os16(Mips_Os16), HasMSA(false), UseTCCInDIV(false), HasSym32(false),
-      HasEVA(false), DisableMadd4(false), HasMT(false), HasCRC(false),
+      HasEVA(false), DisableMadd4(true), HasMT(false), HasCRC(false),
       HasVirt(false), HasGINV(false), UseIndirectJumpsHazard(false),
       StackAlignOverride(StackAlignOverride), TM(TM), TargetTriple(TT),
       TSInfo(), InstrInfo(MipsInstrInfo::create(
@@ -91,6 +91,9 @@ MipsSubtarget::MipsSubtarget(const Triple &TT, StringRef CPU, StringRef FS,
   if (MipsArchVersion == MipsDefault)
     MipsArchVersion = Mips32;
 
+  if (hasMips32r6() || hasMips64r6())
+    DisableMadd4 = false;
+
   // Don't even attempt to generate code for MIPS-I and MIPS-V. They have not
   // been tested and currently exist for the integrated assembler only.
   if (MipsArchVersion == Mips1)
@@ -238,6 +241,7 @@ MipsSubtarget &
 MipsSubtarget::initializeSubtargetDependencies(StringRef CPU, StringRef FS,
                                                const TargetMachine &TM) {
   StringRef CPUName = MIPS_MC::selectMipsCPU(TM.getTargetTriple(), CPU);
+  SubtargetFeatures Features(FS);
 
   // Parse features string.
   ParseSubtargetFeatures(CPUName, /*TuneCPU*/ CPUName, FS);
@@ -260,6 +264,13 @@ MipsSubtarget::initializeSubtargetDependencies(StringRef CPU, StringRef FS,
     report_fatal_error("64-bit code requested on a subtarget that doesn't "
                        "support it!");
 
+  for (const std::string &Feature : Features.getFeatures()) {
+    if (Feature == "+nomadd4")
+      DisableMadd4 = true;
+    else if (Feature == "-nomadd4")
+      DisableMadd4 = false;
+  }
+
   return *this;
 }