diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp | 7 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopStrengthReduce/X86/sibling-loops.ll | 97 |
2 files changed, 104 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp index baef7b9a196..8cdfb3ad3f8 100644 --- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -1119,6 +1119,13 @@ void Cost::RateRegister(const SCEV *Reg, if (isExistingPhi(AR, SE)) return; + // It is bad to allow LSR for current loop to add induction variables + // for its sibling loops. + if (!AR->getLoop()->contains(L)) { + Lose(); + return; + } + // Otherwise, it will be an invariant with respect to Loop L. ++NumRegs; return; diff --git a/llvm/test/Transforms/LoopStrengthReduce/X86/sibling-loops.ll b/llvm/test/Transforms/LoopStrengthReduce/X86/sibling-loops.ll new file mode 100644 index 00000000000..a69d6adc0f0 --- /dev/null +++ b/llvm/test/Transforms/LoopStrengthReduce/X86/sibling-loops.ll @@ -0,0 +1,97 @@ +; RUN: opt -loop-reduce -S < %s | FileCheck %s +; We find it is very bad to allow LSR formula containing SCEVAddRecExpr Reg +; from siblings of current loop. When one loop is LSR optimized, it can +; insert lsr.iv for other sibling loops, which sometimes leads to many extra +; lsr.iv inserted for loops. + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" + +@cond = common local_unnamed_addr global i64 0, align 8 + +; Check there is no extra lsr.iv generated in foo. +; CHECK-LABEL: @foo( +; CHECK-NOT: lsr.iv{{[0-9]+}} = +; +define void @foo(i64 %N) local_unnamed_addr { +entry: + br label %do.body + +do.body: ; preds = %do.body, %entry + %i.0 = phi i64 [ 0, %entry ], [ %inc, %do.body ] + tail call void @goo(i64 %i.0, i64 %i.0) + %inc = add nuw nsw i64 %i.0, 1 + %t0 = load i64, i64* @cond, align 8 + %tobool = icmp eq i64 %t0, 0 + br i1 %tobool, label %do.body2.preheader, label %do.body + +do.body2.preheader: ; preds = %do.body + br label %do.body2 + +do.body2: ; preds = %do.body2.preheader, %do.body2 + %i.1 = phi i64 [ %inc3, %do.body2 ], [ 0, %do.body2.preheader ] + %j.1 = phi i64 [ %inc4, %do.body2 ], [ %inc, %do.body2.preheader ] + tail call void @goo(i64 %i.1, i64 %j.1) + %inc3 = add nuw nsw i64 %i.1, 1 + %inc4 = add nsw i64 %j.1, 1 + %t1 = load i64, i64* @cond, align 8 + %tobool6 = icmp eq i64 %t1, 0 + br i1 %tobool6, label %do.body8.preheader, label %do.body2 + +do.body8.preheader: ; preds = %do.body2 + br label %do.body8 + +do.body8: ; preds = %do.body8.preheader, %do.body8 + %i.2 = phi i64 [ %inc9, %do.body8 ], [ 0, %do.body8.preheader ] + %j.2 = phi i64 [ %inc10, %do.body8 ], [ %inc4, %do.body8.preheader ] + tail call void @goo(i64 %i.2, i64 %j.2) + %inc9 = add nuw nsw i64 %i.2, 1 + %inc10 = add nsw i64 %j.2, 1 + %t2 = load i64, i64* @cond, align 8 + %tobool12 = icmp eq i64 %t2, 0 + br i1 %tobool12, label %do.body14.preheader, label %do.body8 + +do.body14.preheader: ; preds = %do.body8 + br label %do.body14 + +do.body14: ; preds = %do.body14.preheader, %do.body14 + %i.3 = phi i64 [ %inc15, %do.body14 ], [ 0, %do.body14.preheader ] + %j.3 = phi i64 [ %inc16, %do.body14 ], [ %inc10, %do.body14.preheader ] + tail call void @goo(i64 %i.3, i64 %j.3) + %inc15 = add nuw nsw i64 %i.3, 1 + %inc16 = add nsw i64 %j.3, 1 + %t3 = load i64, i64* @cond, align 8 + %tobool18 = icmp eq i64 %t3, 0 + br i1 %tobool18, label %do.body20.preheader, label %do.body14 + +do.body20.preheader: ; preds = %do.body14 + br label %do.body20 + +do.body20: ; preds = %do.body20.preheader, %do.body20 + %i.4 = phi i64 [ %inc21, %do.body20 ], [ 0, %do.body20.preheader ] + %j.4 = phi i64 [ %inc22, %do.body20 ], [ %inc16, %do.body20.preheader ] + tail call void @goo(i64 %i.4, i64 %j.4) + %inc21 = add nuw nsw i64 %i.4, 1 + %inc22 = add nsw i64 %j.4, 1 + %t4 = load i64, i64* @cond, align 8 + %tobool24 = icmp eq i64 %t4, 0 + br i1 %tobool24, label %do.body26.preheader, label %do.body20 + +do.body26.preheader: ; preds = %do.body20 + br label %do.body26 + +do.body26: ; preds = %do.body26.preheader, %do.body26 + %i.5 = phi i64 [ %inc27, %do.body26 ], [ 0, %do.body26.preheader ] + %j.5 = phi i64 [ %inc28, %do.body26 ], [ %inc22, %do.body26.preheader ] + tail call void @goo(i64 %i.5, i64 %j.5) + %inc27 = add nuw nsw i64 %i.5, 1 + %inc28 = add nsw i64 %j.5, 1 + %t5 = load i64, i64* @cond, align 8 + %tobool30 = icmp eq i64 %t5, 0 + br i1 %tobool30, label %do.end31, label %do.body26 + +do.end31: ; preds = %do.body26 + ret void +} + +declare void @goo(i64, i64) local_unnamed_addr + |
