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llvm-mirror/test/Transforms/IndVarSimplify/scevexpander-phi-base-case.ll
Bjorn Pettersson 6aa37cb0b7 [ScalarEvolution] Fix base condition in isNormalAddRecPHI.
Summary:
The function is meant to recurse until it comes upon the
phi it's looking for. However, with the current condition,
it will recurse until it finds anything _but_ the phi.

The function will even fail for simple cases like:
  %i = phi i32 [ %inc, %loop ], ...
  ...
  %inc = add i32 %i, 1

because the base condition will not happen when the phi
is recursed to, and the recursion will end with a 'false'
result since the previous instruction is a phi.

Reviewers: sanjoy, atrick

Reviewed By: sanjoy

Subscribers: Ka-Ka, bjope, llvm-commits

Committing on behalf of: Bevin Hansson (bevinh)

Differential Revision: https://reviews.llvm.org/D40946

llvm-svn: 320700
2017-12-14 14:47:52 +00:00

64 lines
1.9 KiB
LLVM

; RUN: opt -indvars -S < %s | FileCheck %s
define i32 @fn() {
entry:
ret i32 10
}
define i32 @test_nested2(i32 %tnr) {
; CHECK-LABEL: test_nested2
; CHECK-NOT: %indvars.iv
; CHECK: %i.0
; indvars should not replace the i.0 variable with a new one; SCEVExpander
; should determine that the old one is good to reuse.
entry:
%res = alloca i32, align 4
store volatile i32 0, i32* %res, align 4
%call = call i32 @fn()
br label %for.cond
for.cond: ; preds = %for.inc6, %entry
%i.0 = phi i32 [ 0, %entry ], [ %inc7, %for.inc6 ]
%cmp = icmp slt i32 %i.0, %call
br i1 %cmp, label %for.body, label %for.cond.cleanup
for.cond.cleanup: ; preds = %for.cond
br label %for.end8
for.body: ; preds = %for.cond
br label %for.cond1
for.cond1: ; preds = %for.inc, %for.body
%j.0 = phi i32 [ 0, %for.body ], [ %inc5, %for.inc ]
%cmp2 = icmp slt i32 %j.0, %i.0
br i1 %cmp2, label %for.body4, label %for.cond.cleanup3
for.cond.cleanup3: ; preds = %for.cond1
br label %for.end
for.body4: ; preds = %for.cond1
%0 = load volatile i32, i32* %res, align 4
%inc = add nsw i32 %0, 1
store volatile i32 %inc, i32* %res, align 4
br label %for.inc
for.inc: ; preds = %for.body4
%inc5 = add nsw i32 %j.0, 1
br label %for.cond1
for.end: ; preds = %for.cond.cleanup3
br label %for.inc6
for.inc6: ; preds = %for.end
%inc7 = add nsw i32 %i.0, 1
br label %for.cond
for.end8: ; preds = %for.cond.cleanup
%1 = load volatile i32, i32* %res, align 4
%cmp9 = icmp eq i32 %1, 45
%conv = zext i1 %cmp9 to i32
ret i32 %conv
}