From c9cab6442b8158d0080f776cae0cdb2b8a426144 Mon Sep 17 00:00:00 2001
From: David Green <david.green@arm.com>
Date: Mon, 22 Jul 2019 12:51:38 +0000
Subject: [PATCH] [ARM] Fix for MVE VPT block pass

We need to ensure that the number of T's is correct when adding multiple
instructions into the same VPT block.

Differential revision: https://reviews.llvm.org/D65049


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366684 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/Thumb2ITBlockPass.cpp   | 21 ++++++++++++++++++---
 test/CodeGen/Thumb2/mve-vpt-block2.mir |  2 +-
 test/CodeGen/Thumb2/mve-vpt-block3.mir |  2 +-
 test/CodeGen/Thumb2/mve-vpt-block4.mir |  2 +-
 test/CodeGen/Thumb2/mve-vpt-block5.mir |  4 ++--
 5 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/lib/Target/ARM/Thumb2ITBlockPass.cpp b/lib/Target/ARM/Thumb2ITBlockPass.cpp
index 3143eb9840e..2087fd59906 100644
--- a/lib/Target/ARM/Thumb2ITBlockPass.cpp
+++ b/lib/Target/ARM/Thumb2ITBlockPass.cpp
@@ -388,8 +388,6 @@ bool MVEVPTBlock::InsertVPTBlocks(MachineBasicBlock &Block) {
 
     MachineInstrBuilder MIBuilder =
         BuildMI(Block, MBIter, dl, TII->get(ARM::MVE_VPST));
-    // The mask value for the VPST instruction is T = 0b1000 = 8
-    MIBuilder.addImm(VPTMaskValue::T);
 
     MachineBasicBlock::iterator VPSTInsertPos = MIBuilder.getInstr();
     int VPTInstCnt = 1;
@@ -400,12 +398,29 @@ bool MVEVPTBlock::InsertVPTBlocks(MachineBasicBlock &Block) {
       NextPred = getVPTInstrPredicate(*MBIter, PredReg);
     } while (NextPred != ARMVCC::None && NextPred == Pred && ++VPTInstCnt < 4);
 
+    switch (VPTInstCnt) {
+    case 1:
+      MIBuilder.addImm(VPTMaskValue::T);
+      break;
+    case 2:
+      MIBuilder.addImm(VPTMaskValue::TT);
+      break;
+    case 3:
+      MIBuilder.addImm(VPTMaskValue::TTT);
+      break;
+    case 4:
+      MIBuilder.addImm(VPTMaskValue::TTTT);
+      break;
+    default:
+      llvm_unreachable("Unexpected number of instruction in a VPT block");
+    };
+
     MachineInstr *LastMI = &*MBIter;
     finalizeBundle(Block, VPSTInsertPos.getInstrIterator(),
                    ++LastMI->getIterator());
 
     Modified = true;
-    LLVM_DEBUG(dbgs() << "VPT block created for: "; MI->dump(););
+    LLVM_DEBUG(dbgs() << "VPT block created for: "; MI->dump());
 
     ++MBIter;
   }
diff --git a/test/CodeGen/Thumb2/mve-vpt-block2.mir b/test/CodeGen/Thumb2/mve-vpt-block2.mir
index 4c43afe5b1d..7146ecd927f 100644
--- a/test/CodeGen/Thumb2/mve-vpt-block2.mir
+++ b/test/CodeGen/Thumb2/mve-vpt-block2.mir
@@ -64,7 +64,7 @@ body:             |
   bb.0.entry:
     liveins: $q0, $q1, $q2, $q3, $r0
 
-    ; CHECK:       MVE_VPST 8, implicit-def $p0
+    ; CHECK:       MVE_VPST 4, implicit-def $p0
     ; CHECK-NEXT:  renamable $q0 = nnan ninf nsz MVE_VMINNMf32
     ; CHECK-NEXT:  renamable $q1 = nnan ninf nsz MVE_VMINNMf32
 
diff --git a/test/CodeGen/Thumb2/mve-vpt-block3.mir b/test/CodeGen/Thumb2/mve-vpt-block3.mir
index a10e5ea2493..2b8a4dda663 100644
--- a/test/CodeGen/Thumb2/mve-vpt-block3.mir
+++ b/test/CodeGen/Thumb2/mve-vpt-block3.mir
@@ -65,7 +65,7 @@ body:             |
   bb.0.entry:
     liveins: $q0, $q1, $q2, $q3, $r0
 
-    ; CHECK:       MVE_VPST 8, implicit-def $p0
+    ; CHECK:       MVE_VPST 1, implicit-def $p0
     ; CHECK-NEXT:  renamable $q2 = nnan ninf nsz MVE_VMINNMf32
     ; CHECK-NEXT:  renamable $q2 = nnan ninf nsz MVE_VMINNMf32
     ; CHECK-NEXT:  renamable $q0 = nnan ninf nsz MVE_VMINNMf32
diff --git a/test/CodeGen/Thumb2/mve-vpt-block4.mir b/test/CodeGen/Thumb2/mve-vpt-block4.mir
index 2170ed27746..389fb341fd9 100644
--- a/test/CodeGen/Thumb2/mve-vpt-block4.mir
+++ b/test/CodeGen/Thumb2/mve-vpt-block4.mir
@@ -66,7 +66,7 @@ body:             |
   bb.0.entry:
     liveins: $q0, $q1, $q2, $q3, $r0
 
-    ; CHECK:       MVE_VPST 8, implicit-def $p0
+    ; CHECK:       MVE_VPST 1, implicit-def $p0
     ; CHECK-NEXT:  renamable $q2 = nnan ninf nsz MVE_VMINNMf32
     ; CHECK-NEXT:  renamable $q2 = nnan ninf nsz MVE_VMINNMf32
     ; CHECK-NEXT:  renamable $q0 = nnan ninf nsz MVE_VMINNMf32
diff --git a/test/CodeGen/Thumb2/mve-vpt-block5.mir b/test/CodeGen/Thumb2/mve-vpt-block5.mir
index 8ef35b7a823..c0c90903640 100644
--- a/test/CodeGen/Thumb2/mve-vpt-block5.mir
+++ b/test/CodeGen/Thumb2/mve-vpt-block5.mir
@@ -64,13 +64,13 @@ body:             |
     liveins: $q0, $q1, $q2, $r0
 
     ; CHECK:       BUNDLE {{.*}} {
-    ; CHECK-NEXT:    MVE_VPST 8, implicit-def $p0
+    ; CHECK-NEXT:    MVE_VPST 4, implicit-def $p0
     ; CHECK-NEXT:    renamable $q3 = nnan ninf nsz MVE_VMINNMf32 killed renamable $q1, renamable $q2, 1, renamable $vpr, killed renamable $q3
     ; CHECK-NEXT:    renamable $q1 = nnan ninf nsz MVE_VMINNMf32 internal killed renamable $q3, internal renamable $q3, 1, renamable $vpr, undef renamable $q1
     ; CHECK-NEXT:    $q3 = MVE_VORR $q0, $q0, 0, $noreg, internal undef $q3
     ; CHECK-NEXT:  }
     ; CHECK-NEXT:  BUNDLE {{.*}} {
-    ; CHECK-NEXT:    MVE_VPST 8, implicit-def $p0
+    ; CHECK-NEXT:    MVE_VPST 4, implicit-def $p0
     ; CHECK-NEXT:    renamable $q3 = nnan ninf nsz MVE_VMINNMf32 killed renamable $q1, renamable $q2, 1, renamable $vpr, killed renamable $q3
     ; CHECK-NEXT:    renamable $q0 = nnan ninf nsz MVE_VMINNMf32 internal killed renamable $q3, killed renamable $q2, 1, killed renamable $vpr, killed renamable $q0
     ; CHECK-NEXT:    tBX_RET 14, $noreg, implicit internal $q0
-- 
2.11.4.GIT