[llvm] 8a5858c - [TwoAddressInstruction][PowerPC] Call `regOverlapsSet` to find out real clobbers and uses

[Kai Luo via llvm-commits]

Author: Kai Luo
Date: 2020-10-09T02:34:54Z
New Revision: 8a5858c8fd50e6f5767a21854951c3ccba17e8c4

URL: https://github.com/llvm/llvm-project/commit/8a5858c8fd50e6f5767a21854951c3ccba17e8c4
DIFF: https://github.com/llvm/llvm-project/commit/8a5858c8fd50e6f5767a21854951c3ccba17e8c4.diff

LOG: [TwoAddressInstruction][PowerPC] Call `regOverlapsSet` to find out real clobbers and uses

In `rescheduleKillAboveMI`, current implementation uses `SmallSet` to track reg's defs and uses. When comparing, use `SmallSet.count` to find out if it's clobbered or used. It's not correct if involving subregisters. This patch uses `regOverlapsSet` already used by `rescheduleMIBelowKill` to fix the issue.

Fixed https://bugs.llvm.org/show_bug.cgi?id=47707.

Reviewed By: #powerpc, nemanjai

Differential Revision: https://reviews.llvm.org/D88716

Added: 
    llvm/test/CodeGen/PowerPC/pr47707.ll

Modified: 
    llvm/lib/CodeGen/TwoAddressInstructionPass.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
index 615ff4b8789c..4a727902bdd2 100644
--- a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -936,10 +936,10 @@ rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
   if (!KillMI->isSafeToMove(AA, SeenStore))
     return false;
 
-  SmallSet<unsigned, 2> Uses;
-  SmallSet<unsigned, 2> Kills;
-  SmallSet<unsigned, 2> Defs;
-  SmallSet<unsigned, 2> LiveDefs;
+  SmallVector<unsigned, 2> Uses;
+  SmallVector<unsigned, 2> Kills;
+  SmallVector<unsigned, 2> Defs;
+  SmallVector<unsigned, 2> LiveDefs;
   for (const MachineOperand &MO : KillMI->operands()) {
     if (!MO.isReg())
       continue;
@@ -952,13 +952,13 @@ rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
       bool isKill = MO.isKill() || (LIS && isPlainlyKilled(KillMI, MOReg, LIS));
       if (MOReg == Reg && !isKill)
         return false;
-      Uses.insert(MOReg);
+      Uses.push_back(MOReg);
       if (isKill && MOReg != Reg)
-        Kills.insert(MOReg);
+        Kills.push_back(MOReg);
     } else if (Register::isPhysicalRegister(MOReg)) {
-      Defs.insert(MOReg);
+      Defs.push_back(MOReg);
       if (!MO.isDead())
-        LiveDefs.insert(MOReg);
+        LiveDefs.push_back(MOReg);
     }
   }
 
@@ -984,11 +984,11 @@ rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
       if (!MOReg)
         continue;
       if (MO.isUse()) {
-        if (Defs.count(MOReg))
+        if (regOverlapsSet(Defs, MOReg, TRI))
           // Moving KillMI can clobber the physical register if the def has
           // not been seen.
           return false;
-        if (Kills.count(MOReg))
+        if (regOverlapsSet(Kills, MOReg, TRI))
           // Don't want to extend other live ranges and update kills.
           return false;
         if (&OtherMI != MI && MOReg == Reg &&
@@ -1002,12 +1002,13 @@ rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
 
     for (unsigned i = 0, e = OtherDefs.size(); i != e; ++i) {
       unsigned MOReg = OtherDefs[i];
-      if (Uses.count(MOReg))
+      if (regOverlapsSet(Uses, MOReg, TRI))
         return false;
-      if (Register::isPhysicalRegister(MOReg) && LiveDefs.count(MOReg))
+      if (Register::isPhysicalRegister(MOReg) &&
+          regOverlapsSet(LiveDefs, MOReg, TRI))
         return false;
       // Physical register def is seen.
-      Defs.erase(MOReg);
+      Defs.erase(std::remove(Defs.begin(), Defs.end(), MOReg), Defs.end());
     }
   }
 

diff  --git a/llvm/test/CodeGen/PowerPC/pr47707.ll b/llvm/test/CodeGen/PowerPC/pr47707.ll
new file mode 100644
index 000000000000..099fcf10d994
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/pr47707.ll
@@ -0,0 +1,47 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -simplify-mir -verify-machineinstrs < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-n32:64"
+target triple = "powerpc64le-grtev4-linux-gnu"
+
+define void @foo(i64* %p1, i64 %v1, i8 %v2, i64 %v3) {
+; CHECK-LABEL: foo:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    mr 7, 5
+; CHECK-NEXT:    rldimi. 7, 4, 8, 0
+; CHECK-NEXT:    mcrf 1, 0
+; CHECK-NEXT:    andi. 5, 5, 1
+; CHECK-NEXT:    li 5, 0
+; CHECK-NEXT:    std 5, 0(3)
+; CHECK-NEXT:    crnot 20, 6
+; CHECK-NEXT:    bc 4, 1, .LBB0_2
+; CHECK-NEXT:  # %bb.1: # %bb1
+; CHECK-NEXT:    std 4, 0(3)
+; CHECK-NEXT:  .LBB0_2: # %bb2
+; CHECK-NEXT:    bclr 12, 20, 0
+; CHECK-NEXT:  # %bb.3: # %bb3
+; CHECK-NEXT:    std 6, 0(3)
+; CHECK-NEXT:    blr
+  store i64 0, i64* %p1, align 8
+  %ext = zext i8 %v2 to i64
+  %shift = shl nuw i64 %v1, 8
+  %merge = or i64 %shift, %ext
+  %not0 = icmp ne i64 %merge, 0
+  %bit0 = and i64 %ext, 1                 ; and & icmp instructions can be combined
+  %cond1 = icmp eq i64 %bit0, 0           ; to and. and generates condition code to
+  br i1 %cond1, label %bb2, label %bb1    ; be used by this conditional branch
+
+bb1:
+  store i64 %v1, i64* %p1, align 8
+  br label %bb2
+
+bb2:
+  br i1 %not0, label %exit, label %bb3
+
+bb3:
+  store i64 %v3, i64* %p1, align 8
+  br label %exit
+
+exit:
+  ret void
+}