5 files changed, 96 insertions, 26 deletions
diff --git a/llvm/include/llvm/CodeGen/MachineRegisterInfo.h b/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
index 31d484b23ca..be9b89eb77e 100644
--- a/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -581,6 +581,10 @@ public:
   /// function. Writing to a constant register has no effect.
   bool isConstantPhysReg(unsigned PhysReg) const;
 
+  /// Returns true if either isConstantPhysReg or TRI->isCallerPreservedPhysReg
+  /// returns true. This is a utility member function.
+  bool isCallerPreservedOrConstPhysReg(unsigned PhysReg) const;
+
   /// Get an iterator over the pressure sets affected by the given physical or
   /// virtual register. If RegUnit is physical, it must be a register unit (from
   /// MCRegUnitIterator).
diff --git a/llvm/lib/CodeGen/MachineCSE.cpp b/llvm/lib/CodeGen/MachineCSE.cpp
index 32e57a9f938..aaac6ad9336 100644
--- a/llvm/lib/CodeGen/MachineCSE.cpp
+++ b/llvm/lib/CodeGen/MachineCSE.cpp
@@ -250,8 +250,8 @@ bool MachineCSE::hasLivePhysRegDefUses(const MachineInstr *MI,
       continue;
     if (TargetRegisterInfo::isVirtualRegister(Reg))
       continue;
-    // Reading constant physregs is ok.
-    if (!MRI->isConstantPhysReg(Reg))
+    // Reading either caller preserved or constant physregs is ok.
+    if (!MRI->isCallerPreservedOrConstPhysReg(Reg))
       for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
         PhysRefs.insert(*AI);
   }
diff --git a/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
index 84d130fae3c..dfa0a4af334 100644
--- a/llvm/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
@@ -487,6 +487,13 @@ bool MachineRegisterInfo::isConstantPhysReg(unsigned PhysReg) const {
   return true;
 }
 
+bool
+MachineRegisterInfo::isCallerPreservedOrConstPhysReg(unsigned PhysReg) const {
+  const TargetRegisterInfo *TRI = getTargetRegisterInfo();
+  return isConstantPhysReg(PhysReg) ||
+      TRI->isCallerPreservedPhysReg(PhysReg, *MF);
+}
+
 /// markUsesInDebugValueAsUndef - Mark every DBG_VALUE referencing the
 /// specified register as undefined which causes the DBG_VALUE to be
 /// deleted during LiveDebugVariables analysis.
diff --git a/llvm/test/CodeGen/PowerPC/MCSE-caller-preserved-reg.ll b/llvm/test/CodeGen/PowerPC/MCSE-caller-preserved-reg.ll
new file mode 100644
index 00000000000..c72523f3593
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/MCSE-caller-preserved-reg.ll
@@ -0,0 +1,63 @@
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s
+; The instructions addis,addi, bl are used to calculate the address of TLS
+; thread local variables. These TLS access code sequences are generated
+; repeatedly every time the thread local variable is accessed. By communicating
+; to Machine CSE that X2 is guaranteed to have the same value within the same
+; function call (so called Caller Preserved Physical Register), the redudant
+; TLS access code sequences are cleaned up.
+
+%"struct.CC::TT" = type { i64, i32 }
+%class.CC = type { %struct.SS }
+%struct.SS = type { void ()* }
+
+@_ZN2CC2ccE = external thread_local global %"struct.CC::TT", align 8
+
+define noalias i8* @_ZN2CC3funEv(%class.CC* %this) {
+; CHECK-LABEL: _ZN2CC3funEv:
+; CHECK:    mflr 0
+; CHECK-NEXT:    std 0, 16(1)
+; CHECK-NEXT:    stdu 1, -48(1)
+; CHECK-NEXT:    .cfi_def_cfa_offset 48
+; CHECK-NEXT:    .cfi_offset lr, 16
+; CHECK-NEXT:    .cfi_offset r30, -16
+; CHECK-NEXT:    std 30, 32(1)
+; CHECK-NEXT:    mr 30, 3
+; CHECK-NEXT:    ld 12, 0(30)
+; CHECK-NEXT:    std 2, 24(1)
+; CHECK-NEXT:    mtctr 12
+; CHECK-NEXT:    bctrl
+; CHECK-NEXT:    ld 2, 24(1)
+; CHECK-NEXT:    addis 3, 2, _ZN2CC2ccE@got@tlsgd@ha
+; CHECK-NEXT:    addi 3, 3, _ZN2CC2ccE@got@tlsgd@l
+; CHECK-NEXT:    bl __tls_get_addr(_ZN2CC2ccE@tlsgd)
+; CHECK-NEXT:    nop
+; CHECK-NEXT:    ld 4, 0(3)
+; CHECK-NEXT:    cmpldi 4, 0
+; CHECK-NEXT:    beq 0, .LBB0_2
+; CHECK:    addi 4, 3, 8
+; CHECK-NEXT:    mr 3, 30
+; CHECK-NEXT:    bl _ZN2CC3barEPi
+; CHECK-NEXT:    nop
+; CHECK:    ld 30, 32(1)
+; CHECK-NEXT:    li 3, 0
+; CHECK-NEXT:    addi 1, 1, 48
+; CHECK-NEXT:    ld 0, 16(1)
+; CHECK-NEXT:    mtlr 0
+; CHECK-NEXT:    blr
+entry:
+  %foo = getelementptr inbounds %class.CC, %class.CC* %this, i64 0, i32 0, i32 0
+  %0 = load void ()*, void ()** %foo, align 8
+  tail call void %0()
+  %1 = load i64, i64* getelementptr inbounds (%"struct.CC::TT", %"struct.CC::TT"* @_ZN2CC2ccE, i64 0, i32 0)
+  %tobool = icmp eq i64 %1, 0
+  br i1 %tobool, label %if.end, label %if.then
+
+if.then:
+  tail call void @_ZN2CC3barEPi(%class.CC* nonnull %this, i32* getelementptr inbounds (%"struct.CC::TT", %"struct.CC::TT"* @_ZN2CC2ccE, i64 0, i32 1))
+  br label %if.end
+
+if.end:
+  ret i8* null
+}
+
+declare void @_ZN2CC3barEPi(%class.CC*, i32*)
diff --git a/llvm/test/CodeGen/PowerPC/licm-tocReg.ll b/llvm/test/CodeGen/PowerPC/licm-tocReg.ll
index ecdfcba6e3b..824d554991a 100644
--- a/llvm/test/CodeGen/PowerPC/licm-tocReg.ll
+++ b/llvm/test/CodeGen/PowerPC/licm-tocReg.ll
@@ -1,20 +1,20 @@
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s
 
-; The instructions ADDIStocHA/LDtocL are used to calculate the address of 
-; globals. The ones that are in bb.3.if.end could not be hoisted by Machine 
+; The instructions ADDIStocHA/LDtocL are used to calculate the address of
+; globals. The ones that are in bb.3.if.end could not be hoisted by Machine
 ; LICM due to BCTRL_LDinto_toc in bb2.if.then.  This call causes the compiler
 ; to insert a save TOC to stack before the call and load into X2 to restore TOC
-; after. By communicating to Machine LICM that X2 is guaranteed to have the 
+; after. By communicating to Machine LICM that X2 is guaranteed to have the
 ; same value before and after BCTRL_LDinto_toc, these instructions can be
 ; hoisted out of bb.3.if.end to outside of the loop.
 
 ; Pre Machine LICM MIR
 ;
-;body:             
+;body:
 ;  bb.0.entry:
 ;    successors: %bb.2.if.then(0x40000000), %bb.3.if.end(0x40000000)
 ;    liveins: %x3
-;  
+;
 ;    %4 = COPY %x3
 ;    %5 = ADDIStocHA %x2, @ga
 ;    %6 = LDtocL @ga, killed %5 :: (load 8 from got)
@@ -26,7 +26,7 @@
 ;    %11 = CMPW killed %7, killed %10
 ;    BCC 44, killed %11, %bb.2.if.then
 ;    B %bb.3.if.end
-;  
+;
 ;  bb.2.if.then:
 ;    %1 = PHI %0, %bb.0.entry, %3, %bb.3.if.end
 ;    ADJCALLSTACKDOWN 32, 0, implicit-def dead %r1, implicit %r1
@@ -41,10 +41,10 @@
 ;    %22 = COPY %x3
 ;    %x3 = COPY %22
 ;    BLR8 implicit %lr8, implicit %rm, implicit %x3
-;  
+;
 ;  bb.3.if.end:
 ;    successors: %bb.2.if.then(0x04000000), %bb.3.if.end(0x7c000000)
-;  
+;
 ;    %2 = PHI %0, %bb.0.entry, %3, %bb.3.if.end
 ;    %12 = ADDI %2, 1
 ;    %13 = ADDIStocHA %x2, @ga
@@ -62,27 +62,23 @@
 @ga = external global i32, align 4
 @gb = external global i32, align 4
 
-; Function Attrs: nounwind
 define signext i32 @test(i32 (i32)* nocapture %FP) local_unnamed_addr #0 {
 ; CHECK-LABEL: test:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    addis 4, 2, .LC0@toc@ha
-; CHECK-NEXT:    addis 5, 2, .LC1@toc@ha
-; CHECK-NEXT:    ld 4, .LC0@toc@l(4)
-; CHECK-NEXT:    ld 5, .LC1@toc@l(5)
-; CHECK-NEXT:    lwz 6, 0(4)
-; CHECK-NEXT:    lwz 5, 0(5)
-; CHECK-NEXT:    cmpw 6, 5
-; CHECK-NEXT:    lwz 5, 0(4)
+; CHECK-NEXT:    addis 6, 2, .LC0@toc@ha
+; CHECK-NEXT:    addis 4, 2, .LC1@toc@ha
+; CHECK-NEXT:    ld 5, .LC1@toc@l(4)
+; CHECK-NEXT:    ld 6, .LC0@toc@l(6)
+; CHECK-NEXT:    lwz 4, 0(5)
+; CHECK-NEXT:    lwz 7, 0(6)
+; CHECK-NEXT:    cmpw 4, 7
+; CHECK-NEXT:    lwz 7, 0(5)
 ; CHECK-NEXT:    mr 4, 3
-; CHECK-NEXT:    bgt 0, .LBB0_3
-; CHECK-NEXT:  # BB#1:
-; CHECK-NEXT:    addis 3, 2, .LC0@toc@ha
-; CHECK-NEXT:    addis 6, 2, .LC1@toc@ha
-; CHECK-NEXT:    ld 3, .LC0@toc@l(3)
-; CHECK-NEXT:    ld 6, .LC1@toc@l(6)
+; CHECK-NEXT:    bgt 0, .LBB0_2
+; CHECK-NOT:    addis {{[0-9]+}}, 2, .LC0@toc@ha
+; CHECK-NOT:    addis {{[0-9]+}}, 2, .LC1@toc@ha
 ; CHECK-NEXT:    .p2align 5
-; CHECK-NEXT:  .LBB0_2: # %if.end
+; CHECK-NEXT:  .LBB0_1: # %if.end
 ; CHECK-NOT:    addis {{[0-9]+}}, 2, .LC0@toc@ha
 ; CHECK-NOT:    addis {{[0-9]+}}, 2, .LC1@toc@ha
 ; CHECK:    blr