[llvm] r263977 - [Hexagon] Fix reserving emergency spill slots for register scavenger

[Krzysztof Parzyszek via llvm-commits]

Author: kparzysz
Date: Mon Mar 21 14:57:08 2016
New Revision: 263977

URL: http://llvm.org/viewvc/llvm-project?rev=263977&view=rev
Log:
[Hexagon] Fix reserving emergency spill slots for register scavenger

- R10 and R11 are not reserved registers.
- Check for reserved registers when finding unused caller-saved registers.

Modified:
    llvm/trunk/lib/Target/Hexagon/HexagonFrameLowering.cpp
    llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.cpp
    llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.h

Modified: llvm/trunk/lib/Target/Hexagon/HexagonFrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonFrameLowering.cpp?rev=263977&r1=263976&r2=263977&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonFrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/Hexagon/HexagonFrameLowering.cpp Mon Mar 21 14:57:08 2016
@@ -1046,26 +1046,19 @@ void HexagonFrameLowering::processFuncti
 static bool needToReserveScavengingSpillSlots(MachineFunction &MF,
                                               const HexagonRegisterInfo &HRI) {
   MachineRegisterInfo &MRI = MF.getRegInfo();
-  const MCPhysReg *CallerSavedRegs = HRI.getCallerSavedRegs(&MF);
-  // Check for an unused caller-saved register.
-  for ( ; *CallerSavedRegs; ++CallerSavedRegs) {
-    MCPhysReg FreeReg = *CallerSavedRegs;
-    if (MRI.isPhysRegUsed(FreeReg))
-      continue;
-
-    // Check aliased register usage.
-    bool IsCurrentRegUsed = false;
-    for (MCRegAliasIterator AI(FreeReg, &HRI, false); AI.isValid(); ++AI)
-      if (MRI.isPhysRegUsed(*AI)) {
-        IsCurrentRegUsed = true;
-        break;
-      }
-    if (IsCurrentRegUsed)
-      continue;
+  BitVector Reserved = HRI.getReservedRegs(MF);
 
-    // Neither directly used nor used through an aliased register.
+  auto IsUsed = [&HRI,&MRI] (unsigned Reg) -> bool {
+    for (MCRegAliasIterator AI(Reg, &HRI, true); AI.isValid(); ++AI)
+      if (MRI.isPhysRegUsed(*AI))
+        return true;
     return false;
-  }
+  };
+
+  // Check for an unused caller-saved register.
+  for (const MCPhysReg *P = HRI.getCallerSavedRegs(&MF); *P; ++P)
+    if (!IsUsed(*P))
+      return false;
   // All caller-saved registers are used.
   return true;
 }

Modified: llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.cpp?rev=263977&r1=263976&r2=263977&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.cpp Mon Mar 21 14:57:08 2016
@@ -109,8 +109,6 @@ HexagonRegisterInfo::getCalleeSavedRegs(
 BitVector HexagonRegisterInfo::getReservedRegs(const MachineFunction &MF)
   const {
   BitVector Reserved(getNumRegs());
-  Reserved.set(HEXAGON_RESERVED_REG_1);
-  Reserved.set(HEXAGON_RESERVED_REG_2);
   Reserved.set(Hexagon::R29);
   Reserved.set(Hexagon::R30);
   Reserved.set(Hexagon::R31);

Modified: llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.h?rev=263977&r1=263976&r2=263977&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.h (original)
+++ llvm/trunk/lib/Target/Hexagon/HexagonRegisterInfo.h Mon Mar 21 14:57:08 2016
@@ -21,21 +21,6 @@
 #define GET_REGINFO_HEADER
 #include "HexagonGenRegisterInfo.inc"
 
-//
-//  We try not to hard code the reserved registers in our code,
-//  so the following two macros were defined. However, there
-//  are still a few places that R11 and R10 are hard wired.
-//  See below. If, in the future, we decided to change the reserved
-//  register. Don't forget changing the following places.
-//
-//  1. the "Defs" set of STriw_pred in HexagonInstrInfo.td
-//  2. the "Defs" set of LDri_pred in HexagonInstrInfo.td
-//  3. the definition of "IntRegs" in HexagonRegisterInfo.td
-//  4. the definition of "DoubleRegs" in HexagonRegisterInfo.td
-//
-#define HEXAGON_RESERVED_REG_1 Hexagon::R10
-#define HEXAGON_RESERVED_REG_2 Hexagon::R11
-
 namespace llvm {
 class HexagonRegisterInfo : public HexagonGenRegisterInfo {
 public: