[llvm] [DependenceAnalysis] Extending SIV to handle fusable loops (PR #128782)

Alireza Torabian via llvm-commits llvm-commits at lists.llvm.org
Thu Sep 18 15:56:12 PDT 2025


================
@@ -0,0 +1,345 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -disable-output "-passes=print<da>" -aa-pipeline=basic-aa 2>&1 \
+; RUN:   -da-disable-delinearization-checks | FileCheck %s
+
+
+;;  for (long int i = 0; i < n; i++) {
+;;    for (long int j = 0; j < n; j++) {
+;;      for (long int k = 0; k < n; k++) {
+;;        for (long int l = 0; l < n; l++)
+;;          A[i][j][k][l] = i;
+;;      }
+;;      for (long int k = 1; k < n+1; k++) {
+;;        for (long int l = 0; l < n; l++)
+;;          *B++ = A[i + 4][j + 3][k + 2][l + 1];
+
+define void @Fusable0(i64 %n, ptr %A, ptr %B) nounwind uwtable ssp {
+; CHECK-LABEL: 'Fusable0'
+; CHECK-NEXT:  Src: store i64 %i.013, ptr %arrayidx12, align 8 --> Dst: store i64 %i.013, ptr %arrayidx12, align 8
+; CHECK-NEXT:    da analyze - none!
+; CHECK-NEXT:  Src: store i64 %i.013, ptr %arrayidx12, align 8 --> Dst: %0 = load i64, ptr %arrayidx24, align 8
+; CHECK-NEXT:    da analyze - flow [-4 -3]! / assuming 2 fused loop(s): [-4 -3 -3 -1]!
+; CHECK-NEXT:  Src: store i64 %i.013, ptr %arrayidx12, align 8 --> Dst: store i64 %0, ptr %B.addr.34, align 8
+; CHECK-NEXT:    da analyze - confused!
+; CHECK-NEXT:  Src: %0 = load i64, ptr %arrayidx24, align 8 --> Dst: %0 = load i64, ptr %arrayidx24, align 8
+; CHECK-NEXT:    da analyze - none!
+; CHECK-NEXT:  Src: %0 = load i64, ptr %arrayidx24, align 8 --> Dst: store i64 %0, ptr %B.addr.34, align 8
+; CHECK-NEXT:    da analyze - confused!
+; CHECK-NEXT:  Src: store i64 %0, ptr %B.addr.34, align 8 --> Dst: store i64 %0, ptr %B.addr.34, align 8
+; CHECK-NEXT:    da analyze - confused!
+;
+entry:
+  %cmp10 = icmp sgt i64 %n, 0
+  br i1 %cmp10, label %for.cond1.preheader.preheader, label %for.end35
+
+
+for.cond1.preheader.preheader:                    ; preds = %entry
+  br label %for.cond1.preheader
+
+for.cond1.preheader:                              ; preds = %for.cond1.preheader.preheader, %for.inc33
+  %B.addr.014 = phi ptr [ %B.addr.1.lcssa, %for.inc33 ], [ %B, %for.cond1.preheader.preheader ]
+  %i.013 = phi i64 [ %inc34, %for.inc33 ], [ 0, %for.cond1.preheader.preheader ]
+  %cmp28 = icmp sgt i64 %n, 0
+  br i1 %cmp28, label %for.cond4.preheader.preheader, label %for.inc33
+
+for.cond4.preheader.preheader:                    ; preds = %for.cond1.preheader
+  br label %for.cond4.preheader
+
+for.cond4.preheader:                              ; preds = %for.cond4.preheader.preheader, %for.inc30
+  %B.addr.110 = phi ptr [ %B.addr.2.lcssa, %for.inc30 ], [ %B.addr.014, %for.cond4.preheader.preheader ]
+  %j.09 = phi i64 [ %inc31, %for.inc30 ], [ 0, %for.cond4.preheader.preheader ]
+  %cmp53 = icmp sgt i64 %n, 0
+  br i1 %cmp53, label %for.cond7.preheader.preheader, label %for.cond15.loopexit
+
+for.cond7.preheader.preheader:                    ; preds = %for.cond4.preheader
+  br label %for.cond7.preheader
+
+for.cond7.preheader:                              ; preds = %for.cond7.preheader.preheader, %for.inc12
+  %k.07 = phi i64 [ %inc13, %for.inc12 ], [ 0, %for.cond7.preheader.preheader ]
+  %cmp81 = icmp sgt i64 %n, 0
+  br i1 %cmp81, label %for.body9.preheader, label %for.inc12
+
+for.body9.preheader:                              ; preds = %for.cond7.preheader
+  br label %for.body9
+
+for.body9:                                        ; preds = %for.body9.preheader, %for.body9
+  %l.02 = phi i64 [ %inc11, %for.body9 ], [ 0, %for.body9.preheader ]
+  %arrayidx12 = getelementptr inbounds [100 x [100 x [100 x i64]]], ptr %A, i64 %i.013, i64 %j.09, i64 %k.07, i64 %l.02
+  store i64 %i.013, ptr %arrayidx12, align 8
+  %inc11 = add nsw i64 %l.02, 1
+  %exitcond15 = icmp ne i64 %inc11, %n
+  br i1 %exitcond15, label %for.body9, label %for.inc12.loopexit
+
+for.inc12.loopexit:                               ; preds = %for.body9
+  br label %for.inc12
+
+for.inc12:                                        ; preds = %for.inc12.loopexit, %for.cond7.preheader
+  %inc13 = add nsw i64 %k.07, 1
+  %exitcond16 = icmp ne i64 %inc13, %n
+  br i1 %exitcond16, label %for.cond7.preheader, label %for.cond15.loopexit.loopexit
+
+for.cond15.loopexit.loopexit:                     ; preds = %for.inc12
+  br label %for.cond15.loopexit
+
+for.cond15.loopexit:                              ; preds = %for.cond15.loopexit.loopexit, %for.cond4.preheader
+  %cmp163 = icmp sgt i64 %n, 0
+  br i1 %cmp163, label %for.cond18.preheader.preheader, label %for.inc30
+
+for.cond18.preheader.preheader:                   ; preds = %for.cond15.loopexit
+  br label %for.cond18.preheader
+
+for.cond18.preheader:                             ; preds = %for.cond18.preheader.preheader, %for.inc27
+  %k14.06 = phi i64 [ %inc28, %for.inc27 ], [ 1, %for.cond18.preheader.preheader ]
+  %B.addr.25 = phi ptr [ %B.addr.3.lcssa, %for.inc27 ], [ %B.addr.110, %for.cond18.preheader.preheader ]
+  %cmp191 = icmp sgt i64 %n, 0
+  br i1 %cmp191, label %for.body20.preheader, label %for.inc27
+
+for.body20.preheader:                             ; preds = %for.cond18.preheader
+  br label %for.body20
+
+for.body20:                                       ; preds = %for.body20.preheader, %for.body20
+  %l17.04 = phi i64 [ %inc25, %for.body20 ], [ 0, %for.body20.preheader ]
+  %B.addr.34 = phi ptr [ %incdec.ptr, %for.body20 ], [ %B.addr.25, %for.body20.preheader ]
+  %add = add nsw i64 %l17.04, 1
+  %add21 = add nsw i64 %k14.06, 2
+  %add22 = add nsw i64 %j.09, 3
+  %add23 = add nsw i64 %i.013, 4
+  %arrayidx24 = getelementptr inbounds [100 x [100 x [100 x i64]]], ptr %A, i64 %add23, i64 %add22, i64 %add21, i64 %add
+  %0 = load i64, ptr %arrayidx24, align 8
+  %incdec.ptr = getelementptr inbounds i64, ptr %B.addr.34, i64 1
+  store i64 %0, ptr %B.addr.34, align 8
+  %inc25 = add nsw i64 %l17.04, 1
+  %exitcond = icmp ne i64 %inc25, %n
+  br i1 %exitcond, label %for.body20, label %for.inc27.loopexit
+
+for.inc27.loopexit:                               ; preds = %for.body20
+  %scevgep = getelementptr i64, ptr %B.addr.25, i64 %n
+  br label %for.inc27
+
+for.inc27:                                        ; preds = %for.inc27.loopexit, %for.cond18.preheader
+  %B.addr.3.lcssa = phi ptr [ %B.addr.25, %for.cond18.preheader ], [ %scevgep, %for.inc27.loopexit ]
+  %inc28 = add nsw i64 %k14.06, 1
+  %inc29 = add nsw i64 %n, 1
+  %exitcond17 = icmp ne i64 %inc28, %inc29
+  br i1 %exitcond17, label %for.cond18.preheader, label %for.inc30.loopexit
+
+for.inc30.loopexit:                               ; preds = %for.inc27
+  %B.addr.3.lcssa.lcssa = phi ptr [ %B.addr.3.lcssa, %for.inc27 ]
+  br label %for.inc30
+
+for.inc30:                                        ; preds = %for.inc30.loopexit, %for.cond15.loopexit
+  %B.addr.2.lcssa = phi ptr [ %B.addr.110, %for.cond15.loopexit ], [ %B.addr.3.lcssa.lcssa, %for.inc30.loopexit ]
+  %inc31 = add nsw i64 %j.09, 1
+  %exitcond18 = icmp ne i64 %inc31, %n
+  br i1 %exitcond18, label %for.cond4.preheader, label %for.inc33.loopexit
+
+for.inc33.loopexit:                               ; preds = %for.inc30
+  %B.addr.2.lcssa.lcssa = phi ptr [ %B.addr.2.lcssa, %for.inc30 ]
+  br label %for.inc33
+
+for.inc33:                                        ; preds = %for.inc33.loopexit, %for.cond1.preheader
+  %B.addr.1.lcssa = phi ptr [ %B.addr.014, %for.cond1.preheader ], [ %B.addr.2.lcssa.lcssa, %for.inc33.loopexit ]
+  %inc34 = add nsw i64 %i.013, 1
+  %exitcond19 = icmp ne i64 %inc34, %n
+  br i1 %exitcond19, label %for.cond1.preheader, label %for.end35.loopexit
+
+for.end35.loopexit:                               ; preds = %for.inc33
+  br label %for.end35
+
+for.end35:                                        ; preds = %for.end35.loopexit, %entry
+  ret void
+}
+
+
+;;  for (long int i = 0; i < 10; i++)
+;;    A[4*i + 2] = i;
+;;  for (long int j = 0; j < 10; j++)
+;;    tmp = A[j + 2];
+
+define void @Fusable1(ptr %A, ptr %B) nounwind uwtable ssp {
+; CHECK-LABEL: 'Fusable1'
+; CHECK-NEXT:  Src: store i64 %i.03, ptr %arrayidx, align 4 --> Dst: store i64 %i.03, ptr %arrayidx, align 4
+; CHECK-NEXT:    da analyze - none!
+; CHECK-NEXT:  Src: store i64 %i.03, ptr %arrayidx, align 4 --> Dst: %0 = load i64, ptr %arrayidx7, align 4
+; CHECK-NEXT:    da analyze - flow [|<]! / assuming 1 fused loop(s): [<=|<]!
+; CHECK-NEXT:  Src: %0 = load i64, ptr %arrayidx7, align 4 --> Dst: %0 = load i64, ptr %arrayidx7, align 4
+; CHECK-NEXT:    da analyze - none!
+;
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.03 = phi i64 [ 0, %entry ], [ %inc, %for.body ]
+  %mul = shl nsw i64 %i.03, 2
+  %add = add nsw i64 %mul, 2
+
+  %arrayidx = getelementptr inbounds i64, ptr %A, i64 %add
+  store i64 %i.03, ptr %arrayidx, align 4
+  %inc = add nsw i64 %i.03, 1
+  %exitcond5 = icmp ne i64 %inc, 10
+  br i1 %exitcond5, label %for.body, label %for.body4.preheader
+
+for.body4.preheader:                              ; preds = %for.body
+  br label %for.body4
+
+for.body4:                                        ; preds = %for.body4.preheader, %for.body4
+  %j.02 = phi i64 [ %inc9, %for.body4 ], [ 0, %for.body4.preheader ]
+  %add64 = add nsw i64 %j.02, 2
+  %arrayidx7 = getelementptr inbounds i64, ptr %A, i64 %add64
+  %0 = load i64, ptr %arrayidx7, align 4
+  %inc9 = add nsw i64 %j.02, 1
+  %exitcond = icmp ne i64 %inc9, 10
+  br i1 %exitcond, label %for.body4, label %for.end10
+
+for.end10:                                        ; preds = %for.body4
+  ret void
+}
+
+;; No information with fused loops assumption is gnerated as MIV test is not
+;; supported on separate loops yet. 
+;;  for (long int i = 0; i < n; i++) {
+;;    for (long int j = 0; j < n; j++) {
+;;      for (long int k = 0; k < n; k++) {
+;;        for (long int l = 0; l < n; l++)
+;;          A[i][j][k][l] = i;
+;;      }
+;;      for (long int k = 1; k < n+1; k++) {
+;;        for (long int l = 0; l < n; l++)
+;;          *B++ = A[i + 4][j + 3][k + 2][k + l];
+
+define void @NonFusable0(i64 %n, ptr %A, ptr %B) nounwind uwtable ssp {
----------------
1997alireza wrote:

Another case added.

https://github.com/llvm/llvm-project/pull/128782


More information about the llvm-commits mailing list