[PowerPC] Fix assert from machine verify pass that unmatched register class about fcmp selection in fast-isel

Bad machine code: Illegal virtual register for instruction

function: TestULE
basic block: %bb.0 entry (0x1000a39b158)
instruction: %2:crrc = FCMPUD %1:vsfrc, %3:f8rc
operand 1: %1:vsfrc

Fix assert about missing match between fcmp instruction and register class. 
We should use vsx related cmp instruction xvcmpudp instead of fcmpu when vsx is opened.

add -verifymachineinstrs option into related test cases to enable the verify pass.


Differential Revision: https://reviews.llvm.org/D55686

llvm-svn: 350685

Author: wuzish

llvm/lib/Target/PowerPC/PPCFastISel.cpp

@@ -861,8 +861,20 @@ bool PPCFastISel::PPCEmitCmp(const Value *SrcValue1, const Value *SrcValue2,
     }
   }
 
+  unsigned SrcReg1 = getRegForValue(SrcValue1);
+  if (SrcReg1 == 0)
+    return false;
+
+  unsigned SrcReg2 = 0;
+  if (!UseImm) {
+    SrcReg2 = getRegForValue(SrcValue2);
+    if (SrcReg2 == 0)
+      return false;
+  }
+
   unsigned CmpOpc;
   bool NeedsExt = false;
+  auto RC = MRI.getRegClass(SrcReg1);
   switch (SrcVT.SimpleTy) {
     default: return false;
     case MVT::f32:
@@ -879,8 +891,11 @@ bool PPCFastISel::PPCEmitCmp(const Value *SrcValue1, const Value *SrcValue2,
             CmpOpc = PPC::EFSCMPGT;
             break;
         }
-      } else
+      } else if (isVSSRCRegClass(RC)) {
+        llvm_unreachable("Unsupposed f32 VSX comparison");
+      } else {
         CmpOpc = PPC::FCMPUS;
+      }
       break;
     case MVT::f64:
       if (HasSPE) {
@@ -896,8 +911,11 @@ bool PPCFastISel::PPCEmitCmp(const Value *SrcValue1, const Value *SrcValue2,
             CmpOpc = PPC::EFDCMPGT;
             break;
         }
-      } else
+      } else if (isVSFRCRegClass(RC)) {
+        CmpOpc = PPC::XSCMPUDP;
+      } else {
         CmpOpc = PPC::FCMPUD;
+      }
       break;
     case MVT::i1:
     case MVT::i8:
@@ -918,17 +936,6 @@ bool PPCFastISel::PPCEmitCmp(const Value *SrcValue1, const Value *SrcValue2,
       break;
   }
 
-  unsigned SrcReg1 = getRegForValue(SrcValue1);
-  if (SrcReg1 == 0)
-    return false;
-
-  unsigned SrcReg2 = 0;
-  if (!UseImm) {
-    SrcReg2 = getRegForValue(SrcValue2);
-    if (SrcReg2 == 0)
-      return false;
-  }
-
   if (NeedsExt) {
     unsigned ExtReg = createResultReg(&PPC::GPRCRegClass);
     if (!PPCEmitIntExt(SrcVT, SrcReg1, MVT::i32, ExtReg, IsZExt))

llvm/test/CodeGen/PowerPC/fast-isel-fcmp-nan.ll

@@ -1,4 +1,4 @@
-; RUN: llc -mtriple powerpc64le-unknown-linux-gnu -fast-isel -O0 < %s | FileCheck %s
+; RUN: llc -verify-machineinstrs -mtriple powerpc64le-unknown-linux-gnu -fast-isel -O0 < %s | FileCheck %s
 
 define i1 @TestULT(double %t0) {
 ; CHECK-LABEL: TestULT:
@@ -17,7 +17,7 @@ good:
 
 define i1 @TestULE(double %t0) {
 ; CHECK-LABEL: TestULE:
-; CHECK: fcmpu
+; CHECK: xscmpudp
 ; CHECK-NEXT: ble
 ; CHECK: blr
 entry:
@@ -33,7 +33,7 @@ good:
 
 define i1 @TestUNE(double %t0) {
 ; CHECK-LABEL: TestUNE:
-; CHECK: fcmpu
+; CHECK: xscmpudp
 ; CHECK-NEXT: bne
 ; CHECK: blr
 entry:
@@ -79,7 +79,7 @@ good:
 
 define i1 @TestUGE(double %t0) {
 ; CHECK-LABEL: TestUGE:
-; CHECK: fcmpu
+; CHECK: xscmpudp
 ; CHECK-NEXT: bge
 ; CHECK: blr
 entry:
@@ -95,7 +95,7 @@ good:
 
 define i1 @TestOLT(double %t0) {
 ; CHECK-LABEL: TestOLT:
-; CHECK: fcmpu
+; CHECK: xscmpudp
 ; CHECK-NEXT: blt
 ; CHECK: blr
 entry:
@@ -141,7 +141,7 @@ good:
 
 define i1 @TestOEQ(double %t0) {
 ; CHECK-LABEL: TestOEQ:
-; CHECK: fcmpu
+; CHECK: xscmpudp
 ; CHECK-NEXT: beq
 ; CHECK: blr
 entry:
@@ -157,7 +157,7 @@ good:
 
 define i1 @TestOGT(double %t0) {
 ; CHECK-LABEL: TestOGT:
-; CHECK: fcmpu
+; CHECK: xscmpudp
 ; CHECK-NEXT: bgt
 ; CHECK: blr
 entry:

llvm/test/CodeGen/PowerPC/vsx-self-copy.ll

@@ -1,5 +1,5 @@
-; RUN: llc -mcpu=pwr7 -mattr=+vsx < %s | FileCheck %s
-; RUN: llc -mcpu=pwr7 -mattr=+vsx -fast-isel -O0 < %s | FileCheck %s
+; RUN: llc -mcpu=pwr7 -mattr=+vsx < %s -verify-machineinstrs | FileCheck %s
+; RUN: llc -mcpu=pwr7 -mattr=+vsx -fast-isel -O0 < %s -verify-machineinstrs | FileCheck %s
 target datalayout = "E-m:e-i64:64-n32:64"
 target triple = "powerpc64-unknown-linux-gnu"