Hexagon: Move RuntimeLibcall setting out of TargetLowering (#142543)

RuntimeLibcalls needs to be correct in non-codegen contexts, so
should not be configured in TargetLowering. Hexagon has this exotic,
overly general sounding fast math flag which appear to be untested. I've
renamed and moved it but this should probably be deleted and move to a
combine based on fast math flags.

Author: arsenm

llvm/lib/IR/RuntimeLibcalls.cpp

@@ -7,10 +7,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/IR/RuntimeLibcalls.h"
+#include "llvm/Support/CommandLine.h"
 
 using namespace llvm;
 using namespace RTLIB;
 
+static cl::opt<bool>
+    HexagonEnableFastMathRuntimeCalls("hexagon-fast-math", cl::Hidden,
+                                      cl::desc("Enable Fast Math processing"));
+
 /// Set default libcall names. If a target wants to opt-out of a libcall it
 /// should be placed here.
 void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
@@ -302,4 +307,42 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
     for (auto &E : RTLibCallCommon)
       setLibcallName(E.Code, E.Name);
   }
+
+  if (TT.getArch() == Triple::ArchType::hexagon) {
+    setLibcallName(RTLIB::SDIV_I32, "__hexagon_divsi3");
+    setLibcallName(RTLIB::SDIV_I64, "__hexagon_divdi3");
+    setLibcallName(RTLIB::UDIV_I32, "__hexagon_udivsi3");
+    setLibcallName(RTLIB::UDIV_I64, "__hexagon_udivdi3");
+    setLibcallName(RTLIB::SREM_I32, "__hexagon_modsi3");
+    setLibcallName(RTLIB::SREM_I64, "__hexagon_moddi3");
+    setLibcallName(RTLIB::UREM_I32, "__hexagon_umodsi3");
+    setLibcallName(RTLIB::UREM_I64, "__hexagon_umoddi3");
+
+    const bool FastMath = HexagonEnableFastMathRuntimeCalls;
+    // This is the only fast library function for sqrtd.
+    if (FastMath)
+      setLibcallName(RTLIB::SQRT_F64, "__hexagon_fast2_sqrtdf2");
+
+    // Prefix is: nothing  for "slow-math",
+    //            "fast2_" for V5+ fast-math double-precision
+    // (actually, keep fast-math and fast-math2 separate for now)
+    if (FastMath) {
+      setLibcallName(RTLIB::ADD_F64, "__hexagon_fast_adddf3");
+      setLibcallName(RTLIB::SUB_F64, "__hexagon_fast_subdf3");
+      setLibcallName(RTLIB::MUL_F64, "__hexagon_fast_muldf3");
+      setLibcallName(RTLIB::DIV_F64, "__hexagon_fast_divdf3");
+      setLibcallName(RTLIB::DIV_F32, "__hexagon_fast_divsf3");
+    } else {
+      setLibcallName(RTLIB::ADD_F64, "__hexagon_adddf3");
+      setLibcallName(RTLIB::SUB_F64, "__hexagon_subdf3");
+      setLibcallName(RTLIB::MUL_F64, "__hexagon_muldf3");
+      setLibcallName(RTLIB::DIV_F64, "__hexagon_divdf3");
+      setLibcallName(RTLIB::DIV_F32, "__hexagon_divsf3");
+    }
+
+    if (FastMath)
+      setLibcallName(RTLIB::SQRT_F32, "__hexagon_fast2_sqrtf");
+    else
+      setLibcallName(RTLIB::SQRT_F32, "__hexagon_sqrtf");
+  }
 }

llvm/lib/Target/Hexagon/HexagonISelLowering.cpp

@@ -73,9 +73,6 @@ static cl::opt<bool>
     EnableHexSDNodeSched("enable-hexagon-sdnode-sched", cl::Hidden,
                          cl::desc("Enable Hexagon SDNode scheduling"));
 
-static cl::opt<bool> EnableFastMath("ffast-math", cl::Hidden,
-                                    cl::desc("Enable Fast Math processing"));
-
 static cl::opt<int> MinimumJumpTables("minimum-jump-tables", cl::Hidden,
                                       cl::init(5),
                                       cl::desc("Set minimum jump tables"));
@@ -1850,46 +1847,6 @@ HexagonTargetLowering::HexagonTargetLowering(const TargetMachine &TM,
     initializeHVXLowering();
 
   computeRegisterProperties(&HRI);
-
-  //
-  // Library calls for unsupported operations
-  //
-  bool FastMath  = EnableFastMath;
-
-  setLibcallName(RTLIB::SDIV_I32, "__hexagon_divsi3");
-  setLibcallName(RTLIB::SDIV_I64, "__hexagon_divdi3");
-  setLibcallName(RTLIB::UDIV_I32, "__hexagon_udivsi3");
-  setLibcallName(RTLIB::UDIV_I64, "__hexagon_udivdi3");
-  setLibcallName(RTLIB::SREM_I32, "__hexagon_modsi3");
-  setLibcallName(RTLIB::SREM_I64, "__hexagon_moddi3");
-  setLibcallName(RTLIB::UREM_I32, "__hexagon_umodsi3");
-  setLibcallName(RTLIB::UREM_I64, "__hexagon_umoddi3");
-
-  // This is the only fast library function for sqrtd.
-  if (FastMath)
-    setLibcallName(RTLIB::SQRT_F64, "__hexagon_fast2_sqrtdf2");
-
-  // Prefix is: nothing  for "slow-math",
-  //            "fast2_" for V5+ fast-math double-precision
-  // (actually, keep fast-math and fast-math2 separate for now)
-  if (FastMath) {
-    setLibcallName(RTLIB::ADD_F64, "__hexagon_fast_adddf3");
-    setLibcallName(RTLIB::SUB_F64, "__hexagon_fast_subdf3");
-    setLibcallName(RTLIB::MUL_F64, "__hexagon_fast_muldf3");
-    setLibcallName(RTLIB::DIV_F64, "__hexagon_fast_divdf3");
-    setLibcallName(RTLIB::DIV_F32, "__hexagon_fast_divsf3");
-  } else {
-    setLibcallName(RTLIB::ADD_F64, "__hexagon_adddf3");
-    setLibcallName(RTLIB::SUB_F64, "__hexagon_subdf3");
-    setLibcallName(RTLIB::MUL_F64, "__hexagon_muldf3");
-    setLibcallName(RTLIB::DIV_F64, "__hexagon_divdf3");
-    setLibcallName(RTLIB::DIV_F32, "__hexagon_divsf3");
-  }
-
-  if (FastMath)
-    setLibcallName(RTLIB::SQRT_F32, "__hexagon_fast2_sqrtf");
-  else
-    setLibcallName(RTLIB::SQRT_F32, "__hexagon_sqrtf");
 }
 
 const char* HexagonTargetLowering::getTargetNodeName(unsigned Opcode) const {