[PowerPC] Remove unnecessary XSRSP instruction
MI peephole will remove unnecessary FRSP instructions. This patch
removes such unnecessary XSRSP.
Reviewed By: steven.zhang
Differential Revision: https://reviews.llvm.org/D77208
diff --git a/llvm/lib/Target/PowerPC/PPCMIPeephole.cpp b/llvm/lib/Target/PowerPC/PPCMIPeephole.cpp
index 74192cb..70d18ed 100644
--- a/llvm/lib/Target/PowerPC/PPCMIPeephole.cpp
+++ b/llvm/lib/Target/PowerPC/PPCMIPeephole.cpp
@@ -541,10 +541,12 @@
if (!P1 || !P2)
break;
- // Remove the passed FRSP instruction if it only feeds this MI and
- // set any uses of that FRSP (in this MI) to the source of the FRSP.
+ // Remove the passed FRSP/XSRSP instruction if it only feeds this MI
+ // and set any uses of that FRSP/XSRSP (in this MI) to the source of
+ // the FRSP/XSRSP.
auto removeFRSPIfPossible = [&](MachineInstr *RoundInstr) {
- if (RoundInstr->getOpcode() == PPC::FRSP &&
+ unsigned Opc = RoundInstr->getOpcode();
+ if ((Opc == PPC::FRSP || Opc == PPC::XSRSP) &&
MRI->hasOneNonDBGUse(RoundInstr->getOperand(0).getReg())) {
Simplified = true;
Register ConvReg1 = RoundInstr->getOperand(1).getReg();
@@ -554,7 +556,7 @@
if (Use.getOperand(i).isReg() &&
Use.getOperand(i).getReg() == FRSPDefines)
Use.getOperand(i).setReg(ConvReg1);
- LLVM_DEBUG(dbgs() << "Removing redundant FRSP:\n");
+ LLVM_DEBUG(dbgs() << "Removing redundant FRSP/XSRSP:\n");
LLVM_DEBUG(RoundInstr->dump());
LLVM_DEBUG(dbgs() << "As it feeds instruction:\n");
LLVM_DEBUG(MI.dump());
diff --git a/llvm/test/CodeGen/PowerPC/mi-simplify-code.mir b/llvm/test/CodeGen/PowerPC/mi-simplify-code.mir
index 15c1c4e..0cfeb94 100644
--- a/llvm/test/CodeGen/PowerPC/mi-simplify-code.mir
+++ b/llvm/test/CodeGen/PowerPC/mi-simplify-code.mir
@@ -56,7 +56,7 @@
# CHECK-LABEL: remove_xsrsp
# CHECK: sldi 4, 4, 2
# CHECK-NEXT: lfsux 0, 3, 4
-# CHECK-NEXT: xsrsp 0, 0
+# CHECK-NOT: xsrsp
# CHECK-NEXT: lfs 1, 8(3)
# CHECK-NEXT: xxmrghd 0, 1, 0
# CHECK-NEXT: xvcvdpsp 34, 0
