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Do not ignore iv uses outside the loop. 

This one slipped through cracks very well.

llvm-svn: 56284
This commit is contained in:
Devang Patel 2008-09-17 17:53:47 +00:00
parent 7293f0f344
commit dca8d3b183
4 changed files with 101 additions and 5 deletions
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22
llvm/lib/Transforms/Scalar/LoopIndexSplit.cpp
View File

@ -111,6 +111,10 @@ namespace {
/// instruction then loop body is executed only for one iteration. In
/// such case eliminate loop structure surrounding this loop body. For
bool processOneIterationLoop(SplitInfo &SD);
/// isOneIterationLoop - Return true if split condition is EQ and
/// the IV is not used outside the loop.
bool isOneIterationLoop(ICmpInst *CI);
void updateLoopBounds(ICmpInst *CI);
/// updateLoopIterationSpace - Current loop body is covered by an AND
@ -248,7 +252,7 @@ bool LoopIndexSplit::runOnLoop(Loop *IncomingLoop, LPPassManager &LPM_Ref) {
SI = SplitData.erase(Delete_SI);
}
}
else if (CI && CI->getPredicate() == ICmpInst::ICMP_EQ) {
else if (isOneIterationLoop(CI)) {
Changed = processOneIterationLoop(SD);
if (Changed) {
++NumIndexSplit;
@ -276,6 +280,22 @@ bool LoopIndexSplit::runOnLoop(Loop *IncomingLoop, LPPassManager &LPM_Ref) {
return Changed;
}
/// isOneIterationLoop - Return true if split condition is EQ and
/// the IV is not used outside the loop.
bool LoopIndexSplit::isOneIterationLoop(ICmpInst *CI) {
if (!CI)
return false;
if (CI->getPredicate() != ICmpInst::ICMP_EQ)
return false;
Value *Incr = IndVar->getIncomingValueForBlock(L->getLoopLatch());
for (Value::use_iterator UI = Incr->use_begin(), E = Incr->use_end();
UI != E; ++UI)
if (!L->contains(cast<Instruction>(*UI)->getParent()))
return false;
return true;
}
/// Return true if V is a induction variable or induction variable's
/// increment for loop L.
void LoopIndexSplit::findIndVar(Value *V, Loop *L) {

3
llvm/test/Transforms/LoopIndexSplit/2008-05-19-IndVar.ll
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@ -1,5 +1,4 @@
; RUN: llvm-as < %s | opt -loop-index-split | llvm-dis | grep tmp8 | count 3
; count 3 = increment + phi + store
; RUN: llvm-as < %s | opt -loop-index-split -stats -disable-output | not grep "loop-index-split"
;PR2294
@g_2 = external global i16 ; <i16*> [#uses=4]
@g_5 = external global i32 ; <i32*> [#uses=1]

78
llvm/test/Transforms/LoopIndexSplit/2008-09-17-IVUse.ll Normal file
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@ -0,0 +1,78 @@
; RUN: llvm-as < %s | opt -loop-index-split -stats -disable-output | not grep "loop-index-split"
; PR 2791
@g_40 = common global i32 0 ; <i32*> [#uses=1]
@g_192 = common global i32 0 ; <i32*> [#uses=2]
@"\01LC" = internal constant [4 x i8] c"%d\0A\00" ; <[4 x i8]*> [#uses=1]
define void @func_29() nounwind {
entry:
%0 = load i32* @g_40, align 4 ; <i32> [#uses=1]
%1 = icmp eq i32 %0, 0 ; <i1> [#uses=1]
%g_192.promoted = load i32* @g_192 ; <i32> [#uses=0]
br i1 %1, label %entry.split.us, label %entry.split
entry.split.us: ; preds = %entry
br label %bb.us
bb.us: ; preds = %bb5.us, %entry.split.us
%i.0.reg2mem.0.us = phi i32 [ 0, %entry.split.us ], [ %3, %bb5.us ] ; <i32> [#uses=2]
%2 = icmp eq i32 %i.0.reg2mem.0.us, 0 ; <i1> [#uses=1]
br i1 %2, label %bb1.us, label %bb5.us
bb5.us: ; preds = %bb1.us, %bb4.us, %bb.us
%iftmp.0.0.us = phi i32 [ 0, %bb4.us ], [ 1, %bb.us ], [ 1, %bb1.us ] ; <i32> [#uses=1]
%3 = add i32 %i.0.reg2mem.0.us, 1 ; <i32> [#uses=3]
%4 = icmp ult i32 %3, 10 ; <i1> [#uses=1]
br i1 %4, label %bb.us, label %bb8.us
bb4.us: ; preds = %bb1.us
br label %bb5.us
bb1.us: ; preds = %bb.us
br i1 true, label %bb4.us, label %bb5.us
bb8.us: ; preds = %bb5.us
%iftmp.0.0.lcssa.us = phi i32 [ %iftmp.0.0.us, %bb5.us ] ; <i32> [#uses=1]
%.lcssa.us = phi i32 [ %3, %bb5.us ] ; <i32> [#uses=1]
br label %bb8.split
entry.split: ; preds = %entry
br label %bb
bb: ; preds = %bb5, %entry.split
%i.0.reg2mem.0 = phi i32 [ 0, %entry.split ], [ %6, %bb5 ] ; <i32> [#uses=2]
%5 = icmp eq i32 %i.0.reg2mem.0, 0 ; <i1> [#uses=1]
br i1 %5, label %bb1, label %bb5
bb1: ; preds = %bb
br i1 false, label %bb4, label %bb5
bb4: ; preds = %bb1
br label %bb5
bb5: ; preds = %bb1, %bb, %bb4
%iftmp.0.0 = phi i32 [ 0, %bb4 ], [ 1, %bb ], [ 1, %bb1 ] ; <i32> [#uses=1]
%6 = add i32 %i.0.reg2mem.0, 1 ; <i32> [#uses=3]
%7 = icmp ult i32 %6, 10 ; <i1> [#uses=1]
br i1 %7, label %bb, label %bb8
bb8: ; preds = %bb5
%iftmp.0.0.lcssa = phi i32 [ %iftmp.0.0, %bb5 ] ; <i32> [#uses=1]
%.lcssa = phi i32 [ %6, %bb5 ] ; <i32> [#uses=1]
br label %bb8.split
bb8.split: ; preds = %bb8.us, %bb8
%iftmp.0.0.lcssa.us-lcssa = phi i32 [ %iftmp.0.0.lcssa, %bb8 ], [ %iftmp.0.0.lcssa.us, %bb8.us ] ; <i32> [#uses=1]
%.lcssa.us-lcssa = phi i32 [ %.lcssa, %bb8 ], [ %.lcssa.us, %bb8.us ] ; <i32> [#uses=1]
store i32 %iftmp.0.0.lcssa.us-lcssa, i32* @g_192
%8 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @"\01LC", i32 0, i32 0), i32 %.lcssa.us-lcssa ) nounwind ; <i32> [#uses=0]
ret void
}
declare i32 @printf(i8*, ...) nounwind
define i32 @main() nounwind {
entry:
call void @func_29( ) nounwind
ret i32 0
}

3
llvm/test/Transforms/LoopIndexSplit/OneIterLoop3-2007-08-17.ll
View File

@ -1,6 +1,5 @@
; Loop is elimianted. Save last value assignments, including induction variable.
; RUN: llvm-as < %s | opt -loop-index-split -disable-output -stats |& \
; RUN: grep "loop-index-split" | count 1
; RUN: llvm-as < %s | opt -loop-index-split -disable-output -stats | not grep "loop-index-split"
declare i32 @foo(i32)
declare i32 @bar(i32, i32)