2015-10-06 23:36:44 +08:00
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; RUN: opt %loadPolly -basicaa -polly-dependences -analyze -polly-dependences-analysis-type=value-based < %s | FileCheck %s -check-prefix=VALUE
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2016-03-23 21:21:02 +08:00
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; RUN: opt %loadPolly -basicaa -polly-dependences -analyze -polly-dependences-analysis-type=memory-based < %s | FileCheck %s -check-prefix=MEMORY
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2016-06-27 22:47:38 +08:00
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; RUN: opt %loadPolly -basicaa -polly-function-dependences -analyze -polly-dependences-analysis-type=value-based < %s | FileCheck %s -check-prefix=FUNC-VALUE
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; RUN: opt %loadPolly -basicaa -polly-function-dependences -analyze -polly-dependences-analysis-type=memory-based < %s | FileCheck %s -check-prefix=FUNC-MEMORY
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2012-11-02 05:28:32 +08:00
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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"
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%struct._IO_FILE = type { i32, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, %struct._IO_marker*, %struct._IO_FILE*, i32, i32, i64, i16, i8, [1 x i8], i8*, i64, i8*, i8*, i8*, i8*, i64, i32, [20 x i8] }
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%struct._IO_marker = type { %struct._IO_marker*, %struct._IO_FILE*, i32 }
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@A = common global [36 x [49 x double]] zeroinitializer, align 8 ; <[36 x [49 x double]]*> [#uses=3]
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@B = common global [36 x [49 x double]] zeroinitializer, align 8 ; <[36 x [49 x double]]*> [#uses=3]
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@C = common global [36 x [49 x double]] zeroinitializer, align 8 ; <[36 x [49 x double]]*> [#uses=4]
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define void @do_pluto_matmult() nounwind {
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entry:
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fence seq_cst
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br label %do.body
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do.body: ; preds = %do.cond42, %entry
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%indvar3 = phi i64 [ %indvar.next4, %do.cond42 ], [ 0, %entry ] ; <i64> [#uses=3]
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br label %do.body1
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do.body1: ; preds = %do.cond36, %do.body
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%indvar1 = phi i64 [ %indvar.next2, %do.cond36 ], [ 0, %do.body ] ; <i64> [#uses=3]
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2015-02-28 03:20:19 +08:00
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%arrayidx5 = getelementptr [36 x [49 x double]], [36 x [49 x double]]* @C, i64 0, i64 %indvar3, i64 %indvar1 ; <double*> [#uses=2]
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2012-11-02 05:28:32 +08:00
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br label %do.body2
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do.body2: ; preds = %do.cond, %do.body1
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%indvar = phi i64 [ %indvar.next, %do.cond ], [ 0, %do.body1 ] ; <i64> [#uses=3]
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2015-02-28 03:20:19 +08:00
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%arrayidx13 = getelementptr [36 x [49 x double]], [36 x [49 x double]]* @A, i64 0, i64 %indvar3, i64 %indvar ; <double*> [#uses=1]
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%arrayidx22 = getelementptr [36 x [49 x double]], [36 x [49 x double]]* @B, i64 0, i64 %indvar, i64 %indvar1 ; <double*> [#uses=1]
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2015-02-28 05:22:50 +08:00
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%tmp6 = load double, double* %arrayidx5 ; <double> [#uses=1]
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2012-11-02 05:28:32 +08:00
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%mul = fmul double 1.000000e+00, %tmp6 ; <double> [#uses=1]
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2015-02-28 05:22:50 +08:00
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%tmp14 = load double, double* %arrayidx13 ; <double> [#uses=1]
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2012-11-02 05:28:32 +08:00
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%mul15 = fmul double 1.000000e+00, %tmp14 ; <double> [#uses=1]
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2015-02-28 05:22:50 +08:00
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%tmp23 = load double, double* %arrayidx22 ; <double> [#uses=1]
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2012-11-02 05:28:32 +08:00
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%mul24 = fmul double %mul15, %tmp23 ; <double> [#uses=1]
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%add = fadd double %mul, %mul24 ; <double> [#uses=1]
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store double %add, double* %arrayidx5
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br label %do.cond
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do.cond: ; preds = %do.body2
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%indvar.next = add i64 %indvar, 1 ; <i64> [#uses=2]
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%exitcond = icmp ne i64 %indvar.next, 36 ; <i1> [#uses=1]
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br i1 %exitcond, label %do.body2, label %do.end
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do.end: ; preds = %do.cond
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br label %do.cond36
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do.cond36: ; preds = %do.end
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%indvar.next2 = add i64 %indvar1, 1 ; <i64> [#uses=2]
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%exitcond5 = icmp ne i64 %indvar.next2, 36 ; <i1> [#uses=1]
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br i1 %exitcond5, label %do.body1, label %do.end39
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do.end39: ; preds = %do.cond36
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br label %do.cond42
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do.cond42: ; preds = %do.end39
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%indvar.next4 = add i64 %indvar3, 1 ; <i64> [#uses=2]
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%exitcond6 = icmp ne i64 %indvar.next4, 36 ; <i1> [#uses=1]
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br i1 %exitcond6, label %do.body, label %do.end45
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do.end45: ; preds = %do.cond42
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fence seq_cst
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ret void
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}
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2016-01-15 08:48:42 +08:00
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; VALUE: RAW dependences:
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2016-01-15 23:54:45 +08:00
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; VALUE-NEXT: { Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, 1 + i2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34 }
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2016-01-15 08:48:42 +08:00
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; VALUE-NEXT: WAR dependences:
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[Polly] [DependenceInfo] change WAR, WAW generation to correct semantics
= Change of WAR, WAW generation: =
- `buildFlow(Sink, MustSource, MaySource, Sink)` treates any flow of the form
`sink <- may source <- must source` as a *may* dependence.
- we used to call:
```lang=cpp, name=old-flow-call.cpp
Flow = buildFlow(MustWrite, MustWrite, Read, Schedule);
WAW = isl_union_flow_get_must_dependence(Flow);
WAR = isl_union_flow_get_may_dependence(Flow);
```
- This caused some WAW dependences to be treated as WAR dependences.
- Incorrect semantics.
- Now, we call WAR and WAW correctly.
== Correct WAW: ==
```lang=cpp, name=new-waw-call.cpp
Flow = buildFlow(Write, MustWrite, MayWrite, Schedule);
WAW = isl_union_flow_get_may_dependence(Flow);
isl_union_flow_free(Flow);
```
== Correct WAR: ==
```lang=cpp, name=new-war-call.cpp
Flow = buildFlow(Write, Read, MustaWrite, Schedule);
WAR = isl_union_flow_get_must_dependence(Flow);
isl_union_flow_free(Flow);
```
- We want the "shortest" WAR possible (exact dependences).
- We mark all the *must-writes* as may-source, reads as must-souce.
- Then, we ask for *must* dependence.
- This removes all the reads that flow through a *must-write*
before reaching a sink.
- Note that we only block ealier writes with *must-writes*. This is
intuitively correct, as we do not want may-writes to block
must-writes.
- Leaves us with direct (R -> W).
- This affects reduction generation since RED is built using WAW and WAR.
= New StrictWAW for Reductions: =
- We used to call:
```lang=cpp,name=old-waw-war-call.cpp
Flow = buildFlow(MustWrite, MustWrite, Read, Schedule);
WAW = isl_union_flow_get_must_dependence(Flow);
WAR = isl_union_flow_get_may_dependence(Flow);
```
- This *is* the right model of WAW we need for reductions, just not in general.
- Reductions need to track only *strict* WAW, without any interfering reductions.
= Explanation: Why the new WAR dependences in tests are correct: =
- We no longer set WAR = WAR - WAW
- Hence, we will have WAR dependences that were originally removed.
- These may look incorrect, but in fact make sense.
== Code: ==
```lang=llvm, name=new-war-dependence.ll
; void manyreductions(long *A) {
; for (long i = 0; i < 1024; i++)
; for (long j = 0; j < 1024; j++)
; S0: *A += 42;
;
; for (long i = 0; i < 1024; i++)
; for (long j = 0; j < 1024; j++)
; S1: *A += 42;
;
```
=== WAR dependence: ===
{ S0[1023, 1023] -> S1[0, 0] }
- Between `S0[1023, 1023]` and `S1[0, 0]`, we will have the dependences:
```lang=cpp, name=dependence-incorrect, counterexample
S0[1023, 1023]:
*-- tmp = *A (load0)--*
WAR 2 add = tmp + 42 |
*-> *A = add (store0) |
WAR 1
S1[0, 0]: |
tmp = *A (load1) |
add = tmp + 42 |
A = add (store1)<-*
```
- One may assume that WAR2 *hides* WAR1 (since store0 happens before
store1). However, within a statement, Polly has no idea about the
ordering of loads and stores.
- Hence, according to Polly, the code may have looked like this:
```lang=cpp, name=dependence-correct
S0[1023, 1023]:
A = add (store0)
tmp = A (load0) ---*
add = A + 42 |
WAR 1
S1[0, 0]: |
tmp = A (load1) |
add = A + 42 |
A = add (store1) <-*
```
- So, Polly generates (correct) WAR dependences. It does not make sense
to remove these dependences, since they are correct with respect to
Polly's model.
Reviewers: grosser, Meinersbur
tags: #polly
Differential revision: https://reviews.llvm.org/D31386
llvm-svn: 299429
2017-04-04 21:08:23 +08:00
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; VALUE-NEXT: { Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, 1 + i2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34 }
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2016-01-15 08:48:42 +08:00
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; VALUE-NEXT: WAW dependences:
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2016-01-15 23:54:45 +08:00
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; VALUE-NEXT: { Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, 1 + i2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34 }
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2016-01-15 08:48:42 +08:00
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; MEMORY: RAW dependences:
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2016-01-15 23:54:45 +08:00
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; MEMORY-NEXT: { Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, o2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35 }
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2016-01-15 08:48:42 +08:00
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; MEMORY-NEXT: WAR dependences:
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2016-01-15 23:54:45 +08:00
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; MEMORY-NEXT: { Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, o2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35 }
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2016-01-15 08:48:42 +08:00
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; MEMORY-NEXT: WAW dependences:
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2016-01-15 23:54:45 +08:00
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; MEMORY-NEXT: { Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, o2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35 }
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2016-06-27 22:47:38 +08:00
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; FUNC-VALUE: RAW dependences:
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2017-05-03 15:57:35 +08:00
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; FUNC-VALUE-NEXT: { [Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2_Write3[]] -> [Stmt_do_body2[i0, i1, 1 + i2] -> Stmt_do_body2_Read0[]] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34; Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, 1 + i2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34 }
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2016-06-27 22:47:38 +08:00
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; FUNC-VALUE-NEXT: WAR dependences:
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2017-07-04 23:54:11 +08:00
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; FUNC-VALUE-NEXT: { [Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2_Read0[]] -> [Stmt_do_body2[i0, i1, 1 + i2] -> Stmt_do_body2_Write3[]] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34; Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, 1 + i2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34 }
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2016-06-27 22:47:38 +08:00
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; FUNC-VALUE-NEXT: WAW dependences:
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2017-05-03 15:57:35 +08:00
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; FUNC-VALUE-NEXT: { [Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2_Write3[]] -> [Stmt_do_body2[i0, i1, 1 + i2] -> Stmt_do_body2_Write3[]] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34; Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, 1 + i2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and 0 <= i2 <= 34 }
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2016-06-27 22:47:38 +08:00
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; FUNC-MEMORY: RAW dependences:
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2017-05-03 15:57:35 +08:00
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; FUNC-MEMORY-NEXT: { [Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2_Write3[]] -> [Stmt_do_body2[i0, i1, o2] -> Stmt_do_body2_Read0[]] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35; Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, o2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35 }
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2016-06-27 22:47:38 +08:00
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; FUNC-MEMORY-NEXT: WAR dependences:
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2017-05-03 15:57:35 +08:00
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; FUNC-MEMORY-NEXT: { [Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2_Read0[]] -> [Stmt_do_body2[i0, i1, o2] -> Stmt_do_body2_Write3[]] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35; Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, o2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35 }
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2016-06-27 22:47:38 +08:00
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; FUNC-MEMORY-NEXT: WAW dependences:
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2017-05-03 15:57:35 +08:00
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; FUNC-MEMORY-NEXT: { [Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2_Write3[]] -> [Stmt_do_body2[i0, i1, o2] -> Stmt_do_body2_Write3[]] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35; Stmt_do_body2[i0, i1, i2] -> Stmt_do_body2[i0, i1, o2] : 0 <= i0 <= 35 and 0 <= i1 <= 35 and i2 >= 0 and i2 < o2 <= 35 }
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