[mips] Add runtime options to enable/disable madd.fmt and msub.fmt

Add options to clang: -mmadd4 and -mno-madd4, use it to enable or disable
generation of madd.fmt and similar instructions respectively, as per GCC.

Patch by Stefan Maksimovic.

Differential Revision: https://reviews.llvm.org/D33401

llvm-svn: 304929

clang/include/clang/Driver/Options.td

@@ -2001,6 +2001,10 @@ def mdspr2 : Flag<["-"], "mdspr2">, Group<m_Group>;
 def mno_dspr2 : Flag<["-"], "mno-dspr2">, Group<m_Group>;
 def msingle_float : Flag<["-"], "msingle-float">, Group<m_Group>;
 def mdouble_float : Flag<["-"], "mdouble-float">, Group<m_Group>;
+def mmadd4 : Flag<["-"], "mmadd4">, Group<m_Group>,
+  HelpText<"Enable the generation of 4-operand madd.s, madd.d and related instructions.">;
+def mno_madd4 : Flag<["-"], "mno-madd4">, Group<m_Group>,
+  HelpText<"Disable the generation of 4-operand madd.s, madd.d and related instructions.">;
 def mmsa : Flag<["-"], "mmsa">, Group<m_Group>,
   HelpText<"Enable MSA ASE (MIPS only)">;
 def mno_msa : Flag<["-"], "mno-msa">, Group<m_Group>,

clang/lib/Basic/Targets.cpp

@@ -7737,6 +7737,7 @@ class MipsTargetInfo : public TargetInfo {
     NoDSP, DSP1, DSP2
   } DspRev;
   bool HasMSA;
+  bool DisableMadd4;
 
 protected:
   bool HasFP64;
@@ -7747,7 +7748,7 @@ public:
       : TargetInfo(Triple), IsMips16(false), IsMicromips(false),
         IsNan2008(false), IsSingleFloat(false), IsNoABICalls(false),
         CanUseBSDABICalls(false), FloatABI(HardFloat), DspRev(NoDSP),
-        HasMSA(false), HasFP64(false) {
+        HasMSA(false), DisableMadd4(false), HasFP64(false) {
     TheCXXABI.set(TargetCXXABI::GenericMIPS);
 
     setABI((getTriple().getArch() == llvm::Triple::mips ||
@@ -7993,6 +7994,9 @@ public:
     if (HasMSA)
       Builder.defineMacro("__mips_msa", Twine(1));
 
+    if (DisableMadd4)
+      Builder.defineMacro("__mips_no_madd4", Twine(1));
+
     Builder.defineMacro("_MIPS_SZPTR", Twine(getPointerWidth(0)));
     Builder.defineMacro("_MIPS_SZINT", Twine(getIntWidth()));
     Builder.defineMacro("_MIPS_SZLONG", Twine(getLongWidth()));
@@ -8155,6 +8159,8 @@ public:
         DspRev = std::max(DspRev, DSP2);
       else if (Feature == "+msa")
         HasMSA = true;
+      else if (Feature == "+nomadd4")
+        DisableMadd4 = true;
       else if (Feature == "+fp64")
         HasFP64 = true;
       else if (Feature == "-fp64")

clang/lib/Driver/ToolChains/Arch/Mips.cpp

@@ -298,6 +298,13 @@ void mips::getMIPSTargetFeatures(const Driver &D, const llvm::Triple &Triple,
 
   AddTargetFeature(Args, Features, options::OPT_mno_odd_spreg,
                    options::OPT_modd_spreg, "nooddspreg");
+
+  if (Arg *A = Args.getLastArg(options::OPT_mmadd4, options::OPT_mno_madd4)) {
+    if (A->getOption().matches(options::OPT_mmadd4))
+      Features.push_back("-nomadd4");
+    else
+      Features.push_back("+nomadd4");
+  }
 }
 
 mips::NanEncoding mips::getSupportedNanEncoding(StringRef &CPU) {

clang/test/CodeGen/mips-madd4.c

@@ -0,0 +1,86 @@
+// RUN: %clang --target=mips64-unknown-linux -S -mmadd4    %s -o -| FileCheck %s -check-prefix=MADD4
+// RUN: %clang --target=mips64-unknown-linux -S -mno-madd4 %s -o -| FileCheck %s -check-prefix=NOMADD4
+// RUN: %clang --target=mips64-unknown-linux -S -mmadd4    -fno-honor-nans %s -o -| FileCheck %s -check-prefix=MADD4-NONAN
+// RUN: %clang --target=mips64-unknown-linux -S -mno-madd4 -fno-honor-nans %s -o -| FileCheck %s -check-prefix=NOMADD4-NONAN
+ 
+float madd_s (float f, float g, float h)
+{
+  return (f * g) + h;
+}
+// MADD4:   madd.s
+// NOMADD4: mul.s
+// NOMADD4: add.s
+
+float msub_s (float f, float g, float h)
+{
+  return (f * g) - h;
+}
+// MADD4:   msub.s
+// NOMADD4: mul.s
+// NOMADD4: sub.s
+
+double madd_d (double f, double g, double h)
+{
+  return (f * g) + h;
+}
+// MADD4:   madd.d
+// NOMADD4: mul.d
+// NOMADD4: add.d
+
+double msub_d (double f, double g, double h)
+{
+  return (f * g) - h;
+}
+// MADD4:   msub.d
+// NOMADD4: mul.d
+// NOMADD4: sub.d
+
+
+float nmadd_s (float f, float g, float h)
+{
+  // FIXME: Zero has been explicitly placed to force generation of a positive
+  // zero in IR until pattern used to match this instruction is changed to
+  // comply with negative zero as well.
+  return 0-((f * g) + h);
+}
+// MADD4-NONAN:   nmadd.s
+// NOMADD4-NONAN: mul.s
+// NOMADD4-NONAN: add.s
+// NOMADD4-NONAN: sub.s
+
+float nmsub_s (float f, float g, float h)
+{
+  // FIXME: Zero has been explicitly placed to force generation of a positive
+  // zero in IR until pattern used to match this instruction is changed to
+  // comply with negative zero as well.
+  return 0-((f * g) - h);
+}
+// MADD4-NONAN:   nmsub.s
+// NOMADD4-NONAN: mul.s
+// NOMADD4-NONAN: sub.s
+// NOMADD4-NONAN: sub.s
+
+double nmadd_d (double f, double g, double h)
+{
+  // FIXME: Zero has been explicitly placed to force generation of a positive
+  // zero in IR until pattern used to match this instruction is changed to
+  // comply with negative zero as well.
+  return 0-((f * g) + h);
+}
+// MADD4-NONAN:   nmadd.d
+// NOMADD4-NONAN: mul.d
+// NOMADD4-NONAN: add.d
+// NOMADD4-NONAN: sub.d
+
+double nmsub_d (double f, double g, double h)
+{
+  // FIXME: Zero has been explicitly placed to force generation of a positive
+  // zero in IR until pattern used to match this instruction is changed to
+  // comply with negative zero as well.
+  return 0-((f * g) - h);
+}
+// MADD4-NONAN:   nmsub.d
+// NOMADD4-NONAN: mul.d
+// NOMADD4-NONAN: sub.d
+// NOMADD4-NONAN: sub.d
+

clang/test/Preprocessor/init.c

@@ -4664,6 +4664,16 @@
 // RUN:   | FileCheck -match-full-lines -check-prefix MIPS-MSA %s
 // MIPS-MSA:#define __mips_msa 1
 //
+// RUN: %clang_cc1 -target-feature +nomadd4 \
+// RUN:   -E -dM -triple=mips-none-none < /dev/null \
+// RUN:   | FileCheck -match-full-lines -check-prefix MIPS-NOMADD4 %s
+// MIPS-NOMADD4:#define __mips_no_madd4 1
+//
+// RUN: %clang_cc1 \
+// RUN:   -E -dM -triple=mips-none-none < /dev/null \
+// RUN:   | FileCheck -match-full-lines -check-prefix MIPS-MADD4 %s
+// MIPS-MADD4-NOT:#define __mips_no_madd4 1
+//
 // RUN: %clang_cc1 -target-cpu mips32r3 -target-feature +nan2008 \
 // RUN:   -E -dM -triple=mips-none-none < /dev/null \
 // RUN:   | FileCheck -match-full-lines -check-prefix MIPS-NAN2008 %s