[GlobalISel][AArch64] Save a copy on G_SELECT by fixing condition to GPR

The condition can never be fed by FPRs, so it should always be on a GPR.

Differential Revision: https://reviews.llvm.org/D65157

llvm-svn: 366854

Author: Jessica Paquette

llvm/lib/Target/AArch64/AArch64RegisterBankInfo.cpp

@@ -702,11 +702,10 @@ AArch64RegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
       break;
 
     // If we're taking in vectors, we have no choice but to put everything on
-    // FPRs.
+    // FPRs, except for the condition. The condition must always be on a GPR.
     LLT SrcTy = MRI.getType(MI.getOperand(2).getReg());
     if (SrcTy.isVector()) {
-      for (unsigned Idx = 0; Idx < 4; ++Idx)
-        OpRegBankIdx[Idx] = PMI_FirstFPR;
+      OpRegBankIdx = {PMI_FirstFPR, PMI_FirstGPR, PMI_FirstFPR, PMI_FirstFPR};
       break;
     }
 
@@ -750,8 +749,7 @@ AArch64RegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
     // If we have more FP constraints than not, then move everything over to
     // FPR.
     if (NumFP >= 2)
-      for (unsigned Idx = 0; Idx < 4; ++Idx)
-        OpRegBankIdx[Idx] = PMI_FirstFPR;
+      OpRegBankIdx = {PMI_FirstFPR, PMI_FirstGPR, PMI_FirstFPR, PMI_FirstFPR};
 
     break;
   }

llvm/test/CodeGen/AArch64/GlobalISel/regbank-fp-use-def.mir

@@ -91,9 +91,8 @@ body:             |
     ; CHECK: [[COPY1:%[0-9]+]]:gpr(s32) = COPY $w1
     ; CHECK: [[COPY2:%[0-9]+]]:gpr(s32) = COPY $w2
     ; CHECK: [[SITOFP:%[0-9]+]]:fpr(s32) = G_SITOFP [[COPY1]](s32)
-    ; CHECK: [[COPY3:%[0-9]+]]:fpr(s1) = COPY [[TRUNC]](s1)
-    ; CHECK: [[COPY4:%[0-9]+]]:fpr(s32) = COPY [[COPY2]](s32)
-    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s32) = G_SELECT [[COPY3]](s1), [[COPY4]], [[SITOFP]]
+    ; CHECK: [[COPY3:%[0-9]+]]:fpr(s32) = COPY [[COPY2]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s32) = G_SELECT [[TRUNC]](s1), [[COPY3]], [[SITOFP]]
     ; CHECK: [[FPTOSI:%[0-9]+]]:gpr(s32) = G_FPTOSI [[SELECT]](s32)
     %0:_(s32) = COPY $w0
     %1:_(s1) = G_TRUNC %3(s32)

llvm/test/CodeGen/AArch64/GlobalISel/regbank-select.mir

@@ -18,8 +18,7 @@ body:             |
     ; CHECK: [[TRUNC:%[0-9]+]]:gpr(s1) = G_TRUNC [[COPY]](s32)
     ; CHECK: [[COPY1:%[0-9]+]]:fpr(s32) = COPY $s0
     ; CHECK: [[COPY2:%[0-9]+]]:fpr(s32) = COPY $s1
-    ; CHECK: [[COPY3:%[0-9]+]]:fpr(s1) = COPY [[TRUNC]](s1)
-    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s32) = G_SELECT [[COPY3]](s1), [[COPY1]], [[COPY2]]
+    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s32) = G_SELECT [[TRUNC]](s1), [[COPY1]], [[COPY2]]
     ; CHECK: $s0 = COPY [[SELECT]](s32)
     ; CHECK: RET_ReallyLR implicit $s0
     %3:_(s32) = COPY $w0
@@ -47,8 +46,7 @@ body:             |
     ; CHECK: [[TRUNC:%[0-9]+]]:gpr(s1) = G_TRUNC [[COPY]](s32)
     ; CHECK: [[COPY1:%[0-9]+]]:fpr(s64) = COPY $d0
     ; CHECK: [[COPY2:%[0-9]+]]:fpr(s64) = COPY $d1
-    ; CHECK: [[COPY3:%[0-9]+]]:fpr(s1) = COPY [[TRUNC]](s1)
-    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s64) = G_SELECT [[COPY3]](s1), [[COPY1]], [[COPY2]]
+    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s64) = G_SELECT [[TRUNC]](s1), [[COPY1]], [[COPY2]]
     ; CHECK: $d0 = COPY [[SELECT]](s64)
     ; CHECK: RET_ReallyLR implicit $d0
     %3:_(s32) = COPY $w0
@@ -75,8 +73,7 @@ body:             |
     ; CHECK: [[TRUNC:%[0-9]+]]:gpr(s1) = G_TRUNC [[COPY]](s32)
     ; CHECK: [[COPY1:%[0-9]+]]:fpr(s64) = COPY $d0
     ; CHECK: [[COPY2:%[0-9]+]]:fpr(s64) = COPY $d1
-    ; CHECK: [[COPY3:%[0-9]+]]:fpr(s1) = COPY [[TRUNC]](s1)
-    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s64) = G_SELECT [[COPY3]](s1), [[COPY1]], [[COPY2]]
+    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s64) = G_SELECT [[TRUNC]](s1), [[COPY1]], [[COPY2]]
     ; CHECK: $x0 = COPY [[SELECT]](s64)
     ; CHECK: RET_ReallyLR implicit $x0
 
@@ -110,9 +107,8 @@ body:             |
     ; CHECK: [[TRUNC:%[0-9]+]]:gpr(s1) = G_TRUNC [[COPY]](s32)
     ; CHECK: [[COPY1:%[0-9]+]]:fpr(s64) = COPY $d0
     ; CHECK: [[COPY2:%[0-9]+]]:gpr(s64) = COPY $x1
-    ; CHECK: [[COPY3:%[0-9]+]]:fpr(s1) = COPY [[TRUNC]](s1)
-    ; CHECK: [[COPY4:%[0-9]+]]:fpr(s64) = COPY [[COPY2]](s64)
-    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s64) = G_SELECT [[COPY3]](s1), [[COPY1]], [[COPY4]]
+    ; CHECK: [[COPY3:%[0-9]+]]:fpr(s64) = COPY [[COPY2]](s64)
+    ; CHECK: [[SELECT:%[0-9]+]]:fpr(s64) = G_SELECT [[TRUNC]](s1), [[COPY1]], [[COPY3]]
     ; CHECK: $d0 = COPY [[SELECT]](s64)
     ; CHECK: RET_ReallyLR implicit $d0