[llvm] r217966 - [FastISel][AArch64] Improve branch selection to support all FP conditions.

Juergen Ributzka juergen at apple.com
Wed Sep 17 10:46:47 PDT 2014


Author: ributzka
Date: Wed Sep 17 12:46:47 2014
New Revision: 217966

URL: http://llvm.org/viewvc/llvm-project?rev=217966&view=rev
Log:
[FastISel][AArch64] Improve branch selection to support all FP conditions.

This adds the last two missing floating-point condition codes (FCMP_UEQ and
FCMP_ONE) also to the branch selection. In these two cases an additonal branch
instruction is required.

This also adds unit tests to checks all the different condition codes.

This is related o rdar://problem/18358882.

Added:
    llvm/trunk/test/CodeGen/AArch64/fast-isel-cmp-branch.ll
Modified:
    llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp

Modified: llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp?rev=217966&r1=217965&r2=217966&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp Wed Sep 17 12:46:47 2014
@@ -1686,16 +1686,55 @@ bool AArch64FastISel::selectBranch(const
 
   AArch64CC::CondCode CC = AArch64CC::NE;
   if (const CmpInst *CI = dyn_cast<CmpInst>(BI->getCondition())) {
-    if (CI->hasOneUse() && (CI->getParent() == I->getParent())) {
-      // We may not handle every CC for now.
-      CC = getCompareCC(CI->getPredicate());
-      if (CC == AArch64CC::AL)
-        return false;
+    if (CI->hasOneUse() && isValueAvailable(CI)) {
+      // Try to optimize or fold the cmp.
+      CmpInst::Predicate Predicate = optimizeCmpPredicate(CI);
+      switch (Predicate) {
+      default:
+        break;
+      case CmpInst::FCMP_FALSE:
+        fastEmitBranch(FBB, DbgLoc);
+        return true;
+      case CmpInst::FCMP_TRUE:
+        fastEmitBranch(TBB, DbgLoc);
+        return true;
+      }
+
+      // Try to take advantage of fallthrough opportunities.
+      if (FuncInfo.MBB->isLayoutSuccessor(TBB)) {
+        std::swap(TBB, FBB);
+        Predicate = CmpInst::getInversePredicate(Predicate);
+      }
 
       // Emit the cmp.
       if (!emitCmp(CI->getOperand(0), CI->getOperand(1), CI->isUnsigned()))
         return false;
 
+      // FCMP_UEQ and FCMP_ONE cannot be checked with a single branch
+      // instruction.
+      CC = getCompareCC(Predicate);
+      AArch64CC::CondCode ExtraCC = AArch64CC::AL;
+      switch (Predicate) {
+      default:
+        break;
+      case CmpInst::FCMP_UEQ:
+        ExtraCC = AArch64CC::EQ;
+        CC = AArch64CC::VS;
+        break;
+      case CmpInst::FCMP_ONE:
+        ExtraCC = AArch64CC::MI;
+        CC = AArch64CC::GT;
+        break;
+      }
+      assert((CC != AArch64CC::AL) && "Unexpected condition code.");
+
+      // Emit the extra branch for FCMP_UEQ and FCMP_ONE.
+      if (ExtraCC != AArch64CC::AL) {
+        BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(AArch64::Bcc))
+            .addImm(ExtraCC)
+            .addMBB(TBB);
+      }
+
       // Emit the branch.
       BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(AArch64::Bcc))
           .addImm(CC)
@@ -1713,8 +1752,8 @@ bool AArch64FastISel::selectBranch(const
     }
   } else if (TruncInst *TI = dyn_cast<TruncInst>(BI->getCondition())) {
     MVT SrcVT;
-    if (TI->hasOneUse() && TI->getParent() == I->getParent() &&
-        (isTypeSupported(TI->getOperand(0)->getType(), SrcVT))) {
+    if (TI->hasOneUse() && isValueAvailable(TI) &&
+        isTypeSupported(TI->getOperand(0)->getType(), SrcVT)) {
       unsigned CondReg = getRegForValue(TI->getOperand(0));
       if (!CondReg)
         return false;
@@ -1749,8 +1788,7 @@ bool AArch64FastISel::selectBranch(const
       fastEmitBranch(FBB, DbgLoc);
       return true;
     }
-  } else if (const ConstantInt *CI =
-                 dyn_cast<ConstantInt>(BI->getCondition())) {
+  } else if (const auto *CI = dyn_cast<ConstantInt>(BI->getCondition())) {
     uint64_t Imm = CI->getZExtValue();
     MachineBasicBlock *Target = (Imm == 0) ? FBB : TBB;
     BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(AArch64::B))
@@ -2534,7 +2572,7 @@ bool AArch64FastISel::foldXALUIntrinsic(
   }
 
   // Check if both instructions are in the same basic block.
-  if (II->getParent() != I->getParent())
+  if (!isValueAvailable(II))
     return false;
 
   // Make sure nothing is in the way

Added: llvm/trunk/test/CodeGen/AArch64/fast-isel-cmp-branch.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/fast-isel-cmp-branch.ll?rev=217966&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/fast-isel-cmp-branch.ll (added)
+++ llvm/trunk/test/CodeGen/AArch64/fast-isel-cmp-branch.ll Wed Sep 17 12:46:47 2014
@@ -0,0 +1,293 @@
+; RUN: llc                             -aarch64-atomic-cfg-tidy=0 -mtriple=aarch64-apple-darwin < %s | FileCheck %s
+; RUN: llc -fast-isel -fast-isel-abort -aarch64-atomic-cfg-tidy=0 -mtriple=aarch64-apple-darwin < %s | FileCheck %s
+
+define i32 @fcmp_oeq(float %x, float %y) {
+; CHECK-LABEL: fcmp_oeq
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.ne {{LBB.+_2}}
+  %1 = fcmp oeq float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_ogt(float %x, float %y) {
+; CHECK-LABEL: fcmp_ogt
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.le {{LBB.+_2}}
+  %1 = fcmp ogt float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_oge(float %x, float %y) {
+; CHECK-LABEL: fcmp_oge
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.lt {{LBB.+_2}}
+  %1 = fcmp oge float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_olt(float %x, float %y) {
+; CHECK-LABEL: fcmp_olt
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.pl {{LBB.+_2}}
+  %1 = fcmp olt float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_ole(float %x, float %y) {
+; CHECK-LABEL: fcmp_ole
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.hi {{LBB.+_2}}
+  %1 = fcmp ole float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_one(float %x, float %y) {
+; CHECK-LABEL: fcmp_one
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.mi
+; CHECK-NEXT:  b.gt
+  %1 = fcmp one float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_ord(float %x, float %y) {
+; CHECK-LABEL: fcmp_ord
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.vs {{LBB.+_2}}
+  %1 = fcmp ord float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_uno(float %x, float %y) {
+; CHECK-LABEL: fcmp_uno
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.vs {{LBB.+_2}}
+  %1 = fcmp uno float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_ueq(float %x, float %y) {
+; CHECK-LABEL: fcmp_ueq
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.eq {{LBB.+_2}}
+; CHECK-NEXT:  b.vs {{LBB.+_2}}
+  %1 = fcmp ueq float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_ugt(float %x, float %y) {
+; CHECK-LABEL: fcmp_ugt
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.ls {{LBB.+_2}}
+  %1 = fcmp ugt float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_uge(float %x, float %y) {
+; CHECK-LABEL: fcmp_uge
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.mi {{LBB.+_2}}
+  %1 = fcmp uge float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_ult(float %x, float %y) {
+; CHECK-LABEL: fcmp_ult
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.ge {{LBB.+_2}}
+  %1 = fcmp ult float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_ule(float %x, float %y) {
+; CHECK-LABEL: fcmp_ule
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.gt {{LBB.+_2}}
+  %1 = fcmp ule float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @fcmp_une(float %x, float %y) {
+; CHECK-LABEL: fcmp_une
+; CHECK:       fcmp s0, s1
+; CHECK-NEXT:  b.eq {{LBB.+_2}}
+  %1 = fcmp une float %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_eq(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_eq
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.ne {{LBB.+_2}}
+  %1 = icmp eq i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_ne(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_ne
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.eq {{LBB.+_2}}
+  %1 = icmp ne i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_ugt(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_ugt
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.ls {{LBB.+_2}}
+  %1 = icmp ugt i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_uge(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_uge
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.lo {{LBB.+_2}}
+  %1 = icmp uge i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_ult(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_ult
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.hs {{LBB.+_2}}
+  %1 = icmp ult i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_ule(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_ule
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.hi {{LBB.+_2}}
+  %1 = icmp ule i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_sgt(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_sgt
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.le {{LBB.+_2}}
+  %1 = icmp sgt i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_sge(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_sge
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.lt {{LBB.+_2}}
+  %1 = icmp sge i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_slt(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_slt
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.ge {{LBB.+_2}}
+  %1 = icmp slt i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+
+define i32 @icmp_sle(i32 %x, i32 %y) {
+; CHECK-LABEL: icmp_sle
+; CHECK:       cmp w0, w1
+; CHECK-NEXT:  b.gt {{LBB.+_2}}
+  %1 = icmp sle i32 %x, %y
+  br i1 %1, label %bb1, label %bb2
+bb2:
+  ret i32 1
+bb1:
+  ret i32 0
+}
+





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