4 files changed, 55 insertions, 0 deletions
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td b/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
index 6e56b0b0502..2874a55bef3 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
@@ -423,6 +423,7 @@ int TWO_PI_INV = 0x3e22f983;
 int FP_UINT_MAX_PLUS_1 = 0x4f800000;    // 1 << 32 in floating point encoding
 int FP32_NEG_ONE = 0xbf800000;
 int FP32_ONE = 0x3f800000;
+int FP64_ONE = 0x3ff0000000000000;
 }
 def CONST : Constants;
 
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index 64975cf1809..9aaa31c29fe 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -281,6 +281,7 @@ SITargetLowering::SITargetLowering(TargetMachine &TM,
   setTargetDAGCombine(ISD::AND);
   setTargetDAGCombine(ISD::OR);
   setTargetDAGCombine(ISD::UINT_TO_FP);
+  setTargetDAGCombine(ISD::FCANONICALIZE);
 
   // All memory operations. Some folding on the pointer operand is done to help
   // matching the constant offsets in the addressing modes.
@@ -2400,6 +2401,46 @@ SDValue SITargetLowering::performClassCombine(SDNode *N,
   return SDValue();
 }
 
+// Constant fold canonicalize.
+SDValue SITargetLowering::performFCanonicalizeCombine(
+  SDNode *N,
+  DAGCombinerInfo &DCI) const {
+  ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
+  if (!CFP)
+    return SDValue();
+
+  SelectionDAG &DAG = DCI.DAG;
+  const APFloat &C = CFP->getValueAPF();
+
+  // Flush denormals to 0 if not enabled.
+  if (C.isDenormal()) {
+    EVT VT = N->getValueType(0);
+    if (VT == MVT::f32 && !Subtarget->hasFP32Denormals())
+      return DAG.getConstantFP(0.0, SDLoc(N), VT);
+
+    if (VT == MVT::f64 && !Subtarget->hasFP64Denormals())
+      return DAG.getConstantFP(0.0, SDLoc(N), VT);
+  }
+
+  if (C.isNaN()) {
+    EVT VT = N->getValueType(0);
+    APFloat CanonicalQNaN = APFloat::getQNaN(C.getSemantics());
+    if (C.isSignaling()) {
+      // Quiet a signaling NaN.
+      return DAG.getConstantFP(CanonicalQNaN, SDLoc(N), VT);
+    }
+
+    // Make sure it is the canonical NaN bitpattern.
+    //
+    // TODO: Can we use -1 as the canonical NaN value since it's an inline
+    // immediate?
+    if (C.bitcastToAPInt() != CanonicalQNaN.bitcastToAPInt())
+      return DAG.getConstantFP(CanonicalQNaN, SDLoc(N), VT);
+  }
+
+  return SDValue(CFP, 0);
+}
+
 static unsigned minMaxOpcToMin3Max3Opc(unsigned Opc) {
   switch (Opc) {
   case ISD::FMAXNUM:
@@ -2747,6 +2788,8 @@ SDValue SITargetLowering::PerformDAGCombine(SDNode *N,
     return performOrCombine(N, DCI);
   case AMDGPUISD::FP_CLASS:
     return performClassCombine(N, DCI);
+  case ISD::FCANONICALIZE:
+    return performFCanonicalizeCombine(N, DCI);
   }
   return AMDGPUTargetLowering::PerformDAGCombine(N, DCI);
 }
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.h b/llvm/lib/Target/AMDGPU/SIISelLowering.h
index 96c2503f400..4e7131a0b5e 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.h
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.h
@@ -55,6 +55,7 @@ class SITargetLowering final : public AMDGPUTargetLowering {
   SDValue performAndCombine(SDNode *N, DAGCombinerInfo &DCI) const;
   SDValue performOrCombine(SDNode *N, DAGCombinerInfo &DCI) const;
   SDValue performClassCombine(SDNode *N, DAGCombinerInfo &DCI) const;
+  SDValue performFCanonicalizeCombine(SDNode *N, DAGCombinerInfo &DCI) const;
 
   SDValue performMinMaxCombine(SDNode *N, DAGCombinerInfo &DCI) const;
 
diff --git a/llvm/lib/Target/AMDGPU/SIInstructions.td b/llvm/lib/Target/AMDGPU/SIInstructions.td
index 3363fcca9ab..4620ec05752 100644
--- a/llvm/lib/Target/AMDGPU/SIInstructions.td
+++ b/llvm/lib/Target/AMDGPU/SIInstructions.td
@@ -3515,6 +3515,16 @@ def : Pat <
 >;
 }
 
+def : Pat<
+  (fcanonicalize f32:$src),
+  (V_MUL_F32_e64 0, CONST.FP32_ONE, 0, $src, 0, 0)
+>;
+
+def : Pat<
+  (fcanonicalize f64:$src),
+  (V_MUL_F64 0, CONST.FP64_ONE, 0, $src, 0, 0)
+>;
+
 //===----------------------------------------------------------------------===//
 // Fract Patterns
 //===----------------------------------------------------------------------===//