[llvm] r257518 - Codegen: [PPC] Handle weighted comparisons when inserting selects.

[Kyle Butt via llvm-commits]

Author: iteratee
Date: Tue Jan 12 15:00:43 2016
New Revision: 257518

URL: http://llvm.org/viewvc/llvm-project?rev=257518&view=rev
Log:
Codegen: [PPC] Handle weighted comparisons when inserting selects.

Only non-weighted predicates were handled in PPCInstrInfo::insertSelect. Handle
the weighted predicates as well.

This latent bug was triggered by r255398, because it added use of the
branch-weighted predicates.

While here, switch over an enum instead of an int to get the compiler to enforce
totality in the future.

Added:
    llvm/trunk/test/CodeGen/PowerPC/2016-01-07-BranchWeightCrash.ll
Modified:
    llvm/trunk/lib/Target/PowerPC/PPCInstrInfo.cpp

Modified: llvm/trunk/lib/Target/PowerPC/PPCInstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCInstrInfo.cpp?rev=257518&r1=257517&r2=257518&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCInstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCInstrInfo.cpp Tue Jan 12 15:00:43 2016
@@ -744,20 +744,43 @@ void PPCInstrInfo::insertSelect(MachineB
          "isel is for regular integer GPRs only");
 
   unsigned OpCode = Is64Bit ? PPC::ISEL8 : PPC::ISEL;
-  unsigned SelectPred = Cond[0].getImm();
+  auto SelectPred = static_cast<PPC::Predicate>(Cond[0].getImm());
 
   unsigned SubIdx;
   bool SwapOps;
   switch (SelectPred) {
-  default: llvm_unreachable("invalid predicate for isel");
-  case PPC::PRED_EQ: SubIdx = PPC::sub_eq; SwapOps = false; break;
-  case PPC::PRED_NE: SubIdx = PPC::sub_eq; SwapOps = true; break;
-  case PPC::PRED_LT: SubIdx = PPC::sub_lt; SwapOps = false; break;
-  case PPC::PRED_GE: SubIdx = PPC::sub_lt; SwapOps = true; break;
-  case PPC::PRED_GT: SubIdx = PPC::sub_gt; SwapOps = false; break;
-  case PPC::PRED_LE: SubIdx = PPC::sub_gt; SwapOps = true; break;
-  case PPC::PRED_UN: SubIdx = PPC::sub_un; SwapOps = false; break;
-  case PPC::PRED_NU: SubIdx = PPC::sub_un; SwapOps = true; break;
+  case PPC::PRED_EQ:
+  case PPC::PRED_EQ_MINUS:
+  case PPC::PRED_EQ_PLUS:
+      SubIdx = PPC::sub_eq; SwapOps = false; break;
+  case PPC::PRED_NE:
+  case PPC::PRED_NE_MINUS:
+  case PPC::PRED_NE_PLUS:
+      SubIdx = PPC::sub_eq; SwapOps = true; break;
+  case PPC::PRED_LT:
+  case PPC::PRED_LT_MINUS:
+  case PPC::PRED_LT_PLUS:
+      SubIdx = PPC::sub_lt; SwapOps = false; break;
+  case PPC::PRED_GE:
+  case PPC::PRED_GE_MINUS:
+  case PPC::PRED_GE_PLUS:
+      SubIdx = PPC::sub_lt; SwapOps = true; break;
+  case PPC::PRED_GT:
+  case PPC::PRED_GT_MINUS:
+  case PPC::PRED_GT_PLUS:
+      SubIdx = PPC::sub_gt; SwapOps = false; break;
+  case PPC::PRED_LE:
+  case PPC::PRED_LE_MINUS:
+  case PPC::PRED_LE_PLUS:
+      SubIdx = PPC::sub_gt; SwapOps = true; break;
+  case PPC::PRED_UN:
+  case PPC::PRED_UN_MINUS:
+  case PPC::PRED_UN_PLUS:
+      SubIdx = PPC::sub_un; SwapOps = false; break;
+  case PPC::PRED_NU:
+  case PPC::PRED_NU_MINUS:
+  case PPC::PRED_NU_PLUS:
+      SubIdx = PPC::sub_un; SwapOps = true; break;
   case PPC::PRED_BIT_SET:   SubIdx = 0; SwapOps = false; break;
   case PPC::PRED_BIT_UNSET: SubIdx = 0; SwapOps = true; break;
   }

Added: llvm/trunk/test/CodeGen/PowerPC/2016-01-07-BranchWeightCrash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/2016-01-07-BranchWeightCrash.ll?rev=257518&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/2016-01-07-BranchWeightCrash.ll (added)
+++ llvm/trunk/test/CodeGen/PowerPC/2016-01-07-BranchWeightCrash.ll Tue Jan 12 15:00:43 2016
@@ -0,0 +1,35 @@
+; RUN: llc <%s | FileCheck %s
+target datalayout = "e-m:e-i64:64-n32:64"
+target triple = "powerpc64le-unknown-linux-gnu"
+
+%struct.buffer_t = type { i64, i8*, [4 x i32], [4 x i32], [4 x i32], i32, i8, i8, [2 x i8] }
+
+declare i32 @__f1(i8*, %struct.buffer_t* noalias)
+
+; CHECK-LABEL: f1:
+define i32 @f1(i8* %__user_context, %struct.buffer_t* noalias %f1.buffer) {
+entry:
+  br i1 undef, label %"assert succeeded", label %"assert failed", !prof !1
+
+"assert failed":                                  ; preds = %entry
+  br label %destructor_block
+
+"assert succeeded":                               ; preds = %entry
+  %__f1_result = call i32 @__f1(i8* %__user_context, %struct.buffer_t* %f1.buffer) #5
+  %0 = icmp eq i32 %__f1_result, 0
+  br i1 %0, label %"assert succeeded11", label %"assert failed10", !prof !1
+
+destructor_block:                                 ; preds = %"assert succeeded11", %"assert failed10", %"assert failed"
+  %1 = phi i32 [ undef, %"assert failed" ], [ %__f1_result, %"assert failed10" ], [ 0, %"assert succeeded11" ]
+  ret i32 %1
+
+"assert failed10":                                ; preds = %"assert succeeded"
+  br label %destructor_block
+
+"assert succeeded11":                             ; preds = %"assert succeeded"
+  br label %destructor_block
+}
+
+attributes #5 = { nounwind }
+
+!1 = !{!"branch_weights", i32 1073741824, i32 0}