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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.

llvm-svn: 257518
This commit is contained in:
Kyle Butt 2016-01-12 21:00:43 +00:00
parent 4635017176
commit cec40806f1
2 changed files with 68 additions and 10 deletions
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43
llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
View File

@ -744,20 +744,43 @@ void PPCInstrInfo::insertSelect(MachineBasicBlock &MBB,
"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;
}

35
llvm/test/CodeGen/PowerPC/2016-01-07-BranchWeightCrash.ll Normal file
View File

@ -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}