Revert "Remove unnecessary call to getAllocatableRegClass"

This reverts commit r252565.

This also includes the revert of the commit mentioned below in order to
avoid breaking tests in AMDGPU:

Revert "AMDGPU: Set isAllocatable = 0 on VS_32/VS_64"

This reverts commit r252674.

llvm-svn: 252956

3 files changed, 16 insertions, 6 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
index 78231d79f6b..436808b5287 100644
--- a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
@@ -79,6 +79,8 @@ unsigned SIRegisterInfo::getRegPressureSetLimit(const MachineFunction &MF,
                                           STI.getMaxWavesPerCU());
   unsigned VGPRLimit = getNumVGPRsAllowed(STI.getMaxWavesPerCU());
 
+  unsigned VSLimit = SGPRLimit + VGPRLimit;
+
   for (regclass_iterator I = regclass_begin(), E = regclass_end();
        I != E; ++I) {
     const TargetRegisterClass *RC = *I;
@@ -86,7 +88,11 @@ unsigned SIRegisterInfo::getRegPressureSetLimit(const MachineFunction &MF,
     unsigned NumSubRegs = std::max((int)RC->getSize() / 4, 1);
     unsigned Limit;
 
-    if (isSGPRClass(RC)) {
+    if (isPseudoRegClass(RC)) {
+      // FIXME: This is a hack. We should never be considering the pressure of
+      // these since no virtual register should ever have this class.
+      Limit = VSLimit;
+    } else if (isSGPRClass(RC)) {
       Limit = SGPRLimit / NumSubRegs;
     } else {
       Limit = VGPRLimit / NumSubRegs;
diff --git a/llvm/lib/Target/AMDGPU/SIRegisterInfo.h b/llvm/lib/Target/AMDGPU/SIRegisterInfo.h
index 3458cec0923..b1389533ec3 100644
--- a/llvm/lib/Target/AMDGPU/SIRegisterInfo.h
+++ b/llvm/lib/Target/AMDGPU/SIRegisterInfo.h
@@ -59,6 +59,13 @@ public:
   /// \returns true if this class contains VGPR registers.
   bool hasVGPRs(const TargetRegisterClass *RC) const;
 
+  /// returns true if this is a pseudoregister class combination of VGPRs and
+  /// SGPRs for operand modeling. FIXME: We should set isAllocatable = 0 on
+  /// them.
+  static bool isPseudoRegClass(const TargetRegisterClass *RC) {
+    return RC == &AMDGPU::VS_32RegClass || RC == &AMDGPU::VS_64RegClass;
+  }
+
   /// \returns A VGPR reg class with the same width as \p SRC
   const TargetRegisterClass *getEquivalentVGPRClass(
                                           const TargetRegisterClass *SRC) const;
diff --git a/llvm/lib/Target/AMDGPU/SIRegisterInfo.td b/llvm/lib/Target/AMDGPU/SIRegisterInfo.td
index 93909cf2fad..e28dd2fdf91 100644
--- a/llvm/lib/Target/AMDGPU/SIRegisterInfo.td
+++ b/llvm/lib/Target/AMDGPU/SIRegisterInfo.td
@@ -272,12 +272,9 @@ def SCSrc_32 : RegInlineOperand<SReg_32> {
 //  VSrc_* Operands with an SGPR, VGPR or a 32-bit immediate
 //===----------------------------------------------------------------------===//
 
-def VS_32 : RegisterClass<"AMDGPU", [i32, f32], 32, (add SReg_32, VGPR_32)> {
-  let isAllocatable = 0;
-}
+def VS_32 : RegisterClass<"AMDGPU", [i32, f32], 32, (add VGPR_32, SReg_32)>;
 
-def VS_64 : RegisterClass<"AMDGPU", [i64, f64], 32, (add SReg_64, VReg_64)> {
-  let isAllocatable = 0;
+def VS_64 : RegisterClass<"AMDGPU", [i64, f64], 32, (add VReg_64, SReg_64)> {
   let CopyCost = 2;
 }