From ff7fc9de6955ba3e00898eb703b3da1a15fb417c Mon Sep 17 00:00:00 2001
From: Gabe Black <gabeblack@google.com>
Date: Mon, 19 Nov 2018 17:30:06 -0800
Subject: [PATCH] cpu: Stop using unions to store FP registers.

These are now accessed only as integer values.

Change-Id: I21ae6537ebbcbaa02890384194ee1ce001c092bb
Reviewed-on: https://gem5-review.googlesource.com/c/14458
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
---
 src/cpu/o3/regfile.hh    | 11 +++--------
 src/cpu/simple_thread.hh | 19 ++++++++-----------
 2 files changed, 11 insertions(+), 19 deletions(-)

diff --git a/src/cpu/o3/regfile.hh b/src/cpu/o3/regfile.hh
index 2f874213f..354fe2bc5 100644
--- a/src/cpu/o3/regfile.hh
+++ b/src/cpu/o3/regfile.hh
@@ -79,17 +79,12 @@ class PhysRegFile
   private:
     static constexpr auto NumVecElemPerVecReg = TheISA::NumVecElemPerVecReg;
 
-    typedef union {
-        FloatReg d;
-        FloatRegBits q;
-    } PhysFloatReg;
-
     /** Integer register file. */
     std::vector<IntReg> intRegFile;
     std::vector<PhysRegId> intRegIds;
 
     /** Floating point register file. */
-    std::vector<PhysFloatReg> floatRegFile;
+    std::vector<FloatRegBits> floatRegFile;
     std::vector<PhysRegId> floatRegIds;
 
     /** Vector register file. */
@@ -191,7 +186,7 @@ class PhysRegFile
     {
         assert(phys_reg->isFloatPhysReg());
 
-        FloatRegBits floatRegBits = floatRegFile[phys_reg->index()].q;
+        FloatRegBits floatRegBits = floatRegFile[phys_reg->index()];
 
         DPRINTF(IEW, "RegFile: Access to float register %i as int, "
                 "has data %#x\n", phys_reg->index(),
@@ -294,7 +289,7 @@ class PhysRegFile
                 phys_reg->index(), (uint64_t)val);
 
         if (!phys_reg->isZeroReg())
-            floatRegFile[phys_reg->index()].q = val;
+            floatRegFile[phys_reg->index()] = val;
     }
 
     /** Sets a vector register to the given value. */
diff --git a/src/cpu/simple_thread.hh b/src/cpu/simple_thread.hh
index 601aa7c07..65491f27a 100644
--- a/src/cpu/simple_thread.hh
+++ b/src/cpu/simple_thread.hh
@@ -109,10 +109,7 @@ class SimpleThread : public ThreadState
     typedef ThreadContext::Status Status;
 
   protected:
-    union {
-        FloatReg f[TheISA::NumFloatRegs];
-        FloatRegBits i[TheISA::NumFloatRegs];
-    } floatRegs;
+    FloatRegBits floatRegs[TheISA::NumFloatRegs];
     TheISA::IntReg intRegs[TheISA::NumIntRegs];
     VecRegContainer vecRegs[TheISA::NumVecRegs];
 #ifdef ISA_HAS_CC_REGS
@@ -230,7 +227,7 @@ class SimpleThread : public ThreadState
     {
         _pcState = 0;
         memset(intRegs, 0, sizeof(intRegs));
-        memset(floatRegs.i, 0, sizeof(floatRegs.i));
+        memset(floatRegs, 0, sizeof(floatRegs));
         for (int i = 0; i < TheISA::NumVecRegs; i++) {
             vecRegs[i].zero();
         }
@@ -258,8 +255,8 @@ class SimpleThread : public ThreadState
         int flatIndex = isa->flattenFloatIndex(reg_idx);
         assert(flatIndex < TheISA::NumFloatRegs);
         FloatRegBits regVal(readFloatRegBitsFlat(flatIndex));
-        DPRINTF(FloatRegs, "Reading float reg %d (%d) bits as %#x, %f.\n",
-                reg_idx, flatIndex, regVal, floatRegs.f[flatIndex]);
+        DPRINTF(FloatRegs, "Reading float reg %d (%d) bits as %#x.\n",
+                reg_idx, flatIndex, regVal);
         return regVal;
     }
 
@@ -388,8 +385,8 @@ class SimpleThread : public ThreadState
         // when checkercpu enabled
         if (flatIndex < TheISA::NumFloatRegs)
             setFloatRegBitsFlat(flatIndex, val);
-        DPRINTF(FloatRegs, "Setting float reg %d (%d) bits to %#x, %#f.\n",
-                reg_idx, flatIndex, val, floatRegs.f[flatIndex]);
+        DPRINTF(FloatRegs, "Setting float reg %d (%d) bits to %#x.\n",
+                reg_idx, flatIndex, val);
     }
 
     void setVecReg(const RegId& reg, const VecRegContainer& val)
@@ -518,9 +515,9 @@ class SimpleThread : public ThreadState
     uint64_t readIntRegFlat(int idx) { return intRegs[idx]; }
     void setIntRegFlat(int idx, uint64_t val) { intRegs[idx] = val; }
 
-    FloatRegBits readFloatRegBitsFlat(int idx) { return floatRegs.i[idx]; }
+    FloatRegBits readFloatRegBitsFlat(int idx) { return floatRegs[idx]; }
     void setFloatRegBitsFlat(int idx, FloatRegBits val) {
-        floatRegs.i[idx] = val;
+        floatRegs[idx] = val;
     }
 
     const VecRegContainer& readVecRegFlat(const RegIndex& reg) const
-- 
2.30.2