[PATCH] D108755: [AArch64][GlobalISel] Use ZExtValue for zext(xor) when invert tb(n)z

[guopeilin via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG5f48c144c58f: [AArch64][GlobalISel] Use ZExtValue for zext(xor) when invert tb(n)z (authored by guopeilin).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D108755/new/

https://reviews.llvm.org/D108755

Files:
  llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
  llvm/test/CodeGen/AArch64/GlobalISel/opt-fold-xor-tbz-tbnz.mir


Index: llvm/test/CodeGen/AArch64/GlobalISel/opt-fold-xor-tbz-tbnz.mir
===================================================================
--- llvm/test/CodeGen/AArch64/GlobalISel/opt-fold-xor-tbz-tbnz.mir
+++ llvm/test/CodeGen/AArch64/GlobalISel/opt-fold-xor-tbz-tbnz.mir
@@ -117,6 +117,38 @@
     RET_ReallyLR
 ...
 ---
+name:            dont_flip_eq_zext
+alignment:       4
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  ; CHECK-LABEL: name: dont_flip_eq_zext
+  ; CHECK: bb.0:
+  ; CHECK:   successors: %bb.0(0x40000000), %bb.1(0x40000000)
+  ; CHECK:   [[COPY:%[0-9]+]]:gpr32 = COPY $wzr
+  ; CHECK:   [[SUBREG_TO_REG:%[0-9]+]]:gpr64all = SUBREG_TO_REG 0, [[COPY]], %subreg.sub_32
+  ; CHECK:   [[COPY1:%[0-9]+]]:gpr64 = COPY [[SUBREG_TO_REG]]
+  ; CHECK:   TBNZX [[COPY1]], 63, %bb.1
+  ; CHECK:   B %bb.0
+  ; CHECK: bb.1:
+  ; CHECK:   RET_ReallyLR
+  bb.0:
+    successors: %bb.0(0x40000000), %bb.1(0x40000000)
+
+    %1:gpr(s32) = G_CONSTANT i32 0
+    %3:gpr(s32) = G_CONSTANT i32 -1
+    %4:gpr(s32) = G_XOR %1, %3
+    %5:gpr(s64) = G_ZEXT %4(s32)
+    %15:gpr(s64) = G_CONSTANT i64 0
+    %13:gpr(s32) = G_ICMP intpred(slt), %5(s64), %15
+    %7:gpr(s1) = G_TRUNC %13(s32)
+    G_BRCOND %7(s1), %bb.1
+    G_BR %bb.0
+  bb.1:
+    RET_ReallyLR
+...
+---
 name:            dont_flip_ne
 alignment:       4
 legalized:       true
Index: llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
===================================================================
--- llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
+++ llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
@@ -1314,6 +1314,7 @@
 static Register getTestBitReg(Register Reg, uint64_t &Bit, bool &Invert,
                               MachineRegisterInfo &MRI) {
   assert(Reg.isValid() && "Expected valid register!");
+  bool HasZext = false;
   while (MachineInstr *MI = getDefIgnoringCopies(Reg, MRI)) {
     unsigned Opc = MI->getOpcode();
 
@@ -1327,6 +1328,9 @@
     // on the truncated x is the same as the bit number on x.
     if (Opc == TargetOpcode::G_ANYEXT || Opc == TargetOpcode::G_ZEXT ||
         Opc == TargetOpcode::G_TRUNC) {
+      if (Opc == TargetOpcode::G_ZEXT)
+        HasZext = true;
+
       Register NextReg = MI->getOperand(1).getReg();
       // Did we find something worth folding?
       if (!NextReg.isValid() || !MRI.hasOneNonDBGUse(NextReg))
@@ -1355,8 +1359,12 @@
         std::swap(ConstantReg, TestReg);
         VRegAndVal = getConstantVRegValWithLookThrough(ConstantReg, MRI);
       }
-      if (VRegAndVal)
-        C = VRegAndVal->Value.getSExtValue();
+      if (VRegAndVal) {
+        if (HasZext)
+          C = VRegAndVal->Value.getZExtValue();
+        else
+          C = VRegAndVal->Value.getSExtValue();
+      }
       break;
     }
     case TargetOpcode::G_ASHR:


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