diff options
| -rw-r--r-- | lib/Transforms/Vectorize/LoopVectorize.cpp | 34 | ||||
| -rw-r--r-- | test/Transforms/LoopVectorize/if-conversion-reduction.ll | 38 |
2 files changed, 58 insertions, 14 deletions
diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp index 3502e9e..ac62b11 100644 --- a/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -1985,20 +1985,20 @@ bool LoopVectorizationLegality::AddReductionVar(PHINode *Phi, // Also, we can't have multiple block-local users. Instruction *Iter = Phi; while (true) { + // If the instruction has no users then this is a broken + // chain and can't be a reduction variable. + if (Iter->use_empty()) + return false; + // Any reduction instr must be of one of the allowed kinds. if (!isReductionInstr(Iter, Kind)) return false; - // Did we found a user inside this block ? + // Did we find a user inside this block ? bool FoundInBlockUser = false; // Did we reach the initial PHI node ? bool FoundStartPHI = false; - // If the instruction has no users then this is a broken - // chain and can't be a reduction variable. - if (Iter->use_empty()) - return false; - // For each of the *users* of iter. for (Value::use_iterator it = Iter->use_begin(), e = Iter->use_end(); it != e; ++it) { @@ -2009,21 +2009,22 @@ bool LoopVectorizationLegality::AddReductionVar(PHINode *Phi, continue; } - // We allow in-loop PHINodes which are not the original reduction PHI - // node. If this PHI is the only user of Iter (happens in IF w/ no ELSE - // structure) then don't skip this PHI. - if (isa<PHINode>(U) && U->getParent() != TheLoop->getHeader() && - TheLoop->contains(U->getParent()) && Iter->getNumUses() > 1) - continue; - // Check if we found the exit user. BasicBlock *Parent = U->getParent(); if (!TheLoop->contains(Parent)) { - // We must have a single exit instruction. + // Exit if you find multiple outside users. if (ExitInstruction != 0) return false; ExitInstruction = Iter; } + + // We allow in-loop PHINodes which are not the original reduction PHI + // node. If this PHI is the only user of Iter (happens in IF w/ no ELSE + // structure) then don't skip this PHI. + if (isa<PHINode>(U) && U->getParent() != TheLoop->getHeader() && + TheLoop->contains(U) && Iter->getNumUses() > 1) + continue; + // We can't have multiple inside users. if (FoundInBlockUser) return false; @@ -2043,6 +2044,11 @@ bool LoopVectorizationLegality::AddReductionVar(PHINode *Phi, Reductions[Phi] = RD; return true; } + + // If we've reached the start PHI but did not find an outside user then + // this is dead code. Abort. + if (FoundStartPHI) + return false; } } diff --git a/test/Transforms/LoopVectorize/if-conversion-reduction.ll b/test/Transforms/LoopVectorize/if-conversion-reduction.ll new file mode 100644 index 0000000..bacf9c0 --- /dev/null +++ b/test/Transforms/LoopVectorize/if-conversion-reduction.ll @@ -0,0 +1,38 @@ +; RUN: opt < %s -loop-vectorize -force-vector-width=4 -enable-if-conversion -dce -instcombine -licm -S | FileCheck %s + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.9.0" + +;CHECK: @reduction_func +;CHECK-NOT: load <4 x i32> +;CHECK: ret i32 +define i32 @reduction_func(i32* nocapture %A, i32 %n) nounwind uwtable readonly ssp { +entry: + %cmp10 = icmp sgt i32 %n, 0 + br i1 %cmp10, label %for.body, label %for.end + +for.body: ; preds = %entry, %for.inc + %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ] + %sum.011 = phi i32 [ %sum.1, %for.inc ], [ 0, %entry ] + %arrayidx = getelementptr inbounds i32* %A, i64 %indvars.iv + %0 = load i32* %arrayidx, align 4 + %cmp1 = icmp sgt i32 %0, 30 + br i1 %cmp1, label %if.then, label %for.inc + +if.then: ; preds = %for.body + %add = add i32 %sum.011, 2 + %add4 = add i32 %add, %0 + br label %for.inc + +for.inc: ; preds = %for.body, %if.then + %sum.1 = phi i32 [ %add4, %if.then ], [ %sum.011, %for.body ] + %indvars.iv.next = add i64 %indvars.iv, 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp eq i32 %lftr.wideiv, %n + br i1 %exitcond, label %for.end, label %for.body + +for.end: ; preds = %for.inc, %entry + %sum.0.lcssa = phi i32 [ 0, %entry ], [ 4, %for.inc ] + ret i32 %sum.0.lcssa +} + |