[llvm] e77cb4a - [SystemZ] Return true from preferZeroCompareBranch().

[Jonas Paulsson via llvm-commits]

Author: Jonas Paulsson
Date: 2021-05-25T10:24:14-05:00
New Revision: e77cb4ae63e932aa8d5d825970c9e67c1491edec

URL: https://github.com/llvm/llvm-project/commit/e77cb4ae63e932aa8d5d825970c9e67c1491edec
DIFF: https://github.com/llvm/llvm-project/commit/e77cb4ae63e932aa8d5d825970c9e67c1491edec.diff

LOG: [SystemZ] Return true from preferZeroCompareBranch().

Review: Ulrich Weigand
Differential Revision: https://reviews.llvm.org/D103057

Added: 
    

Modified: 
    llvm/lib/Target/SystemZ/SystemZISelLowering.h
    llvm/test/CodeGen/SystemZ/codegenprepare-form-OF-ops.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.h b/llvm/lib/Target/SystemZ/SystemZISelLowering.h
index a9f6cd3ae8a4c..21b3e3a1f67fd 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.h
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.h
@@ -423,6 +423,7 @@ class SystemZTargetLowering : public TargetLowering {
     return TargetLoweringBase::getPreferredVectorAction(VT);
   }
   bool isCheapToSpeculateCtlz() const override { return true; }
+  bool preferZeroCompareBranch() const override { return true; }
   EVT getSetCCResultType(const DataLayout &DL, LLVMContext &,
                          EVT) const override;
   bool isFMAFasterThanFMulAndFAdd(const MachineFunction &MF,

diff  --git a/llvm/test/CodeGen/SystemZ/codegenprepare-form-OF-ops.ll b/llvm/test/CodeGen/SystemZ/codegenprepare-form-OF-ops.ll
index 161f4bc2b7658..23d69f5bf1c93 100644
--- a/llvm/test/CodeGen/SystemZ/codegenprepare-form-OF-ops.ll
+++ b/llvm/test/CodeGen/SystemZ/codegenprepare-form-OF-ops.ll
@@ -52,3 +52,41 @@ bb:
   %tmp12 = select i1 %tmp10, i64 %tmp11, i64 %arg
   ret i64 %tmp12
 }
+
+define i32 @optbranch_32(i32 %Arg) {
+; CHECK-LABEL: optbranch_32:
+; CHECK:        alhsik	%r2, %r2, 1
+; CHECK-NEXT:   bler	%r14
+; CHECK-NEXT:   .LBB4_1:
+; CHECK-NEXT: 	lhi	%r2, -1
+; CHECK-NEXT: 	br	%r14
+bb:
+  %i1 = icmp eq i32 %Arg, -1
+  br i1 %i1, label %bb2, label %bb3
+
+bb2:
+  ret i32 -1
+
+bb3:
+  %i4 = add nuw i32 %Arg, 1
+  ret i32 %i4
+}
+
+define i64 @optbranch_64(i64 %Arg) {
+; CHECK-LABEL: optbranch_64:
+; CHECK:        alghsik	%r2, %r2, 1
+; CHECK-NEXT:   bler	%r14
+; CHECK-NEXT:   .LBB5_1:
+; CHECK-NEXT: 	lghi	%r2, -1
+; CHECK-NEXT: 	br	%r14
+bb:
+  %i1 = icmp eq i64 %Arg, -1
+  br i1 %i1, label %bb2, label %bb3
+
+bb2:
+  ret i64 -1
+
+bb3:
+  %i4 = add nuw i64 %Arg, 1
+  ret i64 %i4
+}