Commit cb676a87 authored by Tobias Grosser's avatar Tobias Grosser
Browse files

Only use instructions as insert locations for SCEVExpander 

SCEVExpander, which we are using during code generation, only allows
instructions as insert locations, but breaks in case BasicBlock->end() iterators
are passed to it due to it trying to obtain the basic block in which code should
be generated by calling Instruction->getParent(), which is not defined for
->end() iterators.

This change adds an assert to Polly that ensures we only pass valid instructions
to SCEVExpander and it fixes one case, where we used IRBuilder->SetInsertBlock()
to set an ->end() insert location which was later passed to SCEVExpander.

In general, Polly is always trying to build up the CFG first, before we actually
insert instructions into the CFG sceleton. As a result, each basic block should
already have at least one branch instruction before we start adding code. Hence,
always requiring the IRBuilder insert location to be set to a real instruction
should always be possible.

Thanks Utpal Bora <cs14mtech11017@iith.ac.in> for his help with test case
reduction.

This is a backport from r243830 as it was committed on trunk.

llvm-svn: 246029
parent 49ecb9ef

polly/lib/CodeGen/BlockGenerators.cpp

+3 −1
Original line number Diff line number Diff line
@@ -123,6 +123,8 @@ Value *BlockGenerator::getNewValue(ScopStmt &Stmt, const Value *Old, 
                                      ->getParent()

                                      ->getDataLayout(),

                              "polly");

        assert(Builder.GetInsertPoint() != Builder.GetInsertBlock()->end() &&

               "Only instructions can be insert points for SCEVExpander");

        Value *Expanded = Expander.expandCodeFor(NewScev, Old->getType(),

                                                 Builder.GetInsertPoint());
@@ -1116,7 +1118,7 @@ void RegionGenerator::copyStmt(ScopStmt &Stmt, ValueMapT &GlobalMap, 
    ValueMapT &RegionMap = RegionMaps[BBCopy];

    RegionMap.insert(BlockMap.begin(), BlockMap.end());



    Builder.SetInsertPoint(BBCopy);

    Builder.SetInsertPoint(BICopy);

    copyInstScalar(Stmt, BI, RegionMap, GlobalMap, LTS);

    BICopy->eraseFromParent();

  }

polly/test/Isl/CodeGen/non-affine-phi-node-expansion.ll

0 → 100644
+54 −0
Original line number Diff line number Diff line 
; RUN: opt %loadPolly -polly-codegen -S < %s | FileCheck %s

target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"



%struct.wombat = type {[4 x i32]}



; CHECK: polly.stmt.bb3.entry:                             ; preds = %polly.start

; CHECK:   br label %polly.stmt.bb3



; CHECK: polly.stmt.bb3:                                   ; preds = %polly.stmt.bb3.entry

; CHECK:   %polly.subregion.iv = phi i32 [ 0, %polly.stmt.bb3.entry ]

; CHECK:   %polly.subregion.iv.inc = add i32 %polly.subregion.iv, 1

; CHECK:   br i1 true, label %polly.stmt.bb4, label %polly.stmt.bb5



; CHECK: polly.stmt.bb4:                                   ; preds = %polly.stmt.bb3

; CHECK:   br label %polly.stmt.bb13.exit



; CHECK: polly.stmt.bb5:                                   ; preds = %polly.stmt.bb3

; CHECK:   %tmp7_p_scalar_ = load i32, i32* %B, !alias.scope !0, !noalias !2

; CHECK:   store i32 %tmp7_p_scalar_, i32* %polly.access.cast.arg2, !alias.scope !3, !noalias !4

; CHECK:   br label %polly.stmt.bb13.exit



; Function Attrs: nounwind uwtable

define void @quux(%struct.wombat* %arg, i32* %B) {

bb:

  br i1 undef, label %bb2, label %bb1



bb1:                                              ; preds = %bb

  br label %bb2



bb2:                                              ; preds = %bb1, %bb

  %tmp = phi i1 [ true, %bb ], [ undef, %bb1 ]

  br label %bb3



bb3:                                              ; preds = %bb13, %bb2

  br i1 %tmp, label %bb4, label %bb5



bb4:                                              ; preds = %bb3

  br label %bb13



bb5:                                              ; preds = %bb3

  %tmp7 = load i32, i32* %B

  %tmp12 = getelementptr inbounds %struct.wombat, %struct.wombat* %arg, i64 0, i32 0, i64 0

  store i32 %tmp7, i32* %tmp12

  br label %bb13



bb13:                                             ; preds = %bb5, %bb4

  br i1 false, label %bb3, label %bb14



bb14:                                             ; preds = %bb13

  br label %bb15



bb15:                                             ; preds = %bb14

  unreachable

}