[FastISel][AArch64] Fix and extend the tbz/tbnz pattern matching.

The pattern matching failed to recognize all instances of "-1", because when
comparing against "-1" we didn't use an APInt of the same bitwidth.

This commit fixes this and also adds inverse versions of the conditon to catch
more cases.

llvm-svn: 222722

2 files changed, 176 insertions, 21 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64FastISel.cpp b/llvm/lib/Target/AArch64/AArch64FastISel.cpp
index 612cb00c7bf..fb0326bf0bf 100644
--- a/llvm/lib/Target/AArch64/AArch64FastISel.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FastISel.cpp
@@ -2112,15 +2112,15 @@ bool AArch64FastISel::emitCompareAndBranch(const BranchInst *BI) {
 
   int TestBit = -1;
   bool IsCmpNE;
-  if ((Predicate == CmpInst::ICMP_EQ) || (Predicate == CmpInst::ICMP_NE)) {
-    if (const auto *C = dyn_cast<Constant>(LHS))
-      if (C->isNullValue())
-        std::swap(LHS, RHS);
-
-    if (!isa<Constant>(RHS))
-      return false;
+  switch (Predicate) {
+  default:
+    return false;
+  case CmpInst::ICMP_EQ:
+  case CmpInst::ICMP_NE:
+    if (isa<Constant>(LHS) && cast<Constant>(LHS)->isNullValue())
+      std::swap(LHS, RHS);
 
-    if (!cast<Constant>(RHS)->isNullValue())
+    if (!isa<Constant>(RHS) || !cast<Constant>(RHS)->isNullValue())
       return false;
 
     if (const auto *AI = dyn_cast<BinaryOperator>(LHS))
@@ -2143,26 +2143,27 @@ bool AArch64FastISel::emitCompareAndBranch(const BranchInst *BI) {
       TestBit = 0;
 
     IsCmpNE = Predicate == CmpInst::ICMP_NE;
-  } else if (Predicate == CmpInst::ICMP_SLT) {
-    if (!isa<Constant>(RHS))
-      return false;
-
-    if (!cast<Constant>(RHS)->isNullValue())
+    break;
+  case CmpInst::ICMP_SLT:
+  case CmpInst::ICMP_SGE:
+    if (!isa<Constant>(RHS) || !cast<Constant>(RHS)->isNullValue())
       return false;
 
     TestBit = BW - 1;
-    IsCmpNE = true;
-  } else if (Predicate == CmpInst::ICMP_SGT) {
+    IsCmpNE = Predicate == CmpInst::ICMP_SLT;
+    break;
+  case CmpInst::ICMP_SGT:
+  case CmpInst::ICMP_SLE:
     if (!isa<ConstantInt>(RHS))
       return false;
 
-    if (cast<ConstantInt>(RHS)->getValue() != -1)
+    if (cast<ConstantInt>(RHS)->getValue() != APInt(BW, -1, true))
       return false;
 
     TestBit = BW - 1;
-    IsCmpNE = false;
-  } else
-    return false;
+    IsCmpNE = Predicate == CmpInst::ICMP_SLE;
+    break;
+  } // end switch
 
   static const unsigned OpcTable[2][2][2] = {
     { {AArch64::CBZW,  AArch64::CBZX },
diff --git a/llvm/test/CodeGen/AArch64/fast-isel-tbz.ll b/llvm/test/CodeGen/AArch64/fast-isel-tbz.ll
index d7f46b2cfde..67e81b4cd80 100644
--- a/llvm/test/CodeGen/AArch64/fast-isel-tbz.ll
+++ b/llvm/test/CodeGen/AArch64/fast-isel-tbz.ll
@@ -1,5 +1,5 @@
-; RUN: llc                             -aarch64-atomic-cfg-tidy=0 -verify-machineinstrs -mtriple=aarch64-apple-darwin < %s | FileCheck %s
-; RUN: llc -fast-isel -fast-isel-abort -aarch64-atomic-cfg-tidy=0 -verify-machineinstrs -mtriple=aarch64-apple-darwin < %s | FileCheck %s
+; RUN: llc                             -aarch64-atomic-cfg-tidy=0 -verify-machineinstrs -mtriple=aarch64-apple-darwin < %s | FileCheck --check-prefix=CHECK %s
+; RUN: llc -fast-isel -fast-isel-abort -aarch64-atomic-cfg-tidy=0 -verify-machineinstrs -mtriple=aarch64-apple-darwin < %s | FileCheck --check-prefix=CHECK --check-prefix=FAST %s
 
 define i32 @icmp_eq_i8(i8 zeroext %a) {
 ; CHECK-LABEL: icmp_eq_i8
@@ -121,6 +121,160 @@ bb2:
   ret i32 0
 }
 
+define i32 @icmp_slt_i8(i8 zeroext %a) {
+; FAST-LABEL: icmp_slt_i8
+; FAST:       tbnz w0, #7, {{LBB.+_2}}
+  %1 = icmp slt i8 %a, 0
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_slt_i16(i16 zeroext %a) {
+; FAST-LABEL: icmp_slt_i16
+; FAST:       tbnz w0, #15, {{LBB.+_2}}
+  %1 = icmp slt i16 %a, 0
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_slt_i32(i32 %a) {
+; CHECK-LABEL: icmp_slt_i32
+; CHECK:       tbnz w0, #31, {{LBB.+_2}}
+  %1 = icmp slt i32 %a, 0
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_slt_i64(i64 %a) {
+; CHECK-LABEL: icmp_slt_i64
+; CHECK:       tbnz x0, #63, {{LBB.+_2}}
+  %1 = icmp slt i64 %a, 0
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sge_i8(i8 zeroext %a) {
+; FAST-LABEL: icmp_sge_i8
+; FAST:       tbz w0, #7, {{LBB.+_2}}
+  %1 = icmp sge i8 %a, 0
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sge_i16(i16 zeroext %a) {
+; FAST-LABEL: icmp_sge_i16
+; FAST:       tbz w0, #15, {{LBB.+_2}}
+  %1 = icmp sge i16 %a, 0
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sle_i8(i8 zeroext %a) {
+; FAST-LABEL: icmp_sle_i8
+; FAST:       tbnz w0, #7, {{LBB.+_2}}
+  %1 = icmp sle i8 %a, -1
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sle_i16(i16 zeroext %a) {
+; FAST-LABEL: icmp_sle_i16
+; FAST:       tbnz w0, #15, {{LBB.+_2}}
+  %1 = icmp sle i16 %a, -1
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sle_i32(i32 %a) {
+; CHECK-LABEL: icmp_sle_i32
+; CHECK:       tbnz w0, #31, {{LBB.+_2}}
+  %1 = icmp sle i32 %a, -1
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sle_i64(i64 %a) {
+; CHECK-LABEL: icmp_sle_i64
+; CHECK:       tbnz x0, #63, {{LBB.+_2}}
+  %1 = icmp sle i64 %a, -1
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sgt_i8(i8 zeroext %a) {
+; FAST-LABEL: icmp_sgt_i8
+; FAST:       tbz w0, #7, {{LBB.+_2}}
+  %1 = icmp sgt i8 %a, -1
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sgt_i16(i16 zeroext %a) {
+; FAST-LABEL: icmp_sgt_i16
+; FAST:       tbz w0, #15, {{LBB.+_2}}
+  %1 = icmp sgt i16 %a, -1
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sgt_i32(i32 %a) {
+; CHECK-LABEL: icmp_sgt_i32
+; CHECK:       tbz w0, #31, {{LBB.+_2}}
+  %1 = icmp sgt i32 %a, -1
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
+define i32 @icmp_sgt_i64(i64 %a) {
+; FAST-LABEL: icmp_sgt_i64
+; FAST:       tbz x0, #63, {{LBB.+_2}}
+  %1 = icmp sgt i64 %a, -1
+  br i1 %1, label %bb1, label %bb2, !prof !0
+bb1:
+  ret i32 1
+bb2:
+  ret i32 0
+}
+
 ; Test that we don't fold the 'and' instruction into the compare.
 define i32 @icmp_eq_and_i32(i32 %a, i1 %c) {
 ; CHECK-LABEL: icmp_eq_and_i32