[PATCH] D108601: [SCEV] Infer nuw from nw for addrecs
Philip Reames via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 24 11:05:03 PDT 2021
reames updated this revision to Diff 368404.
reames retitled this revision from "[SCEV] Infer nsw/nuw from nw for addrecs" to "[SCEV] Infer nuw from nw for addrecs".
reames added a comment.
Implement review comment and narrow scope to nuw only.
I'll come back to the nsw case separately, but a) nuw is what's actually blocking me, and b) with the focus on generality in the review comments, we should do the same for nsw which requires a bit more code motion than I want to roll into this patch.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D108601/new/
https://reviews.llvm.org/D108601
Files:
llvm/lib/Analysis/ScalarEvolution.cpp
llvm/test/Analysis/ScalarEvolution/ptrtoint.ll
llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll
Index: llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll
===================================================================
--- llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll
+++ llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll
@@ -511,7 +511,7 @@
; CHECK: loop:
; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ 0, [[ENTRY:%.*]] ]
; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
-; CHECK-NEXT: [[TMP0:%.*]] = mul nsw i64 [[INDVARS_IV]], -1
+; CHECK-NEXT: [[TMP0:%.*]] = mul nuw nsw i64 [[INDVARS_IV]], -1
; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[TMP0]], [[SEXT]]
; CHECK-NEXT: call void @consume.i1(i1 [[TMP1]])
; CHECK-NEXT: call void @consume.i64(i64 [[TMP0]])
Index: llvm/test/Analysis/ScalarEvolution/ptrtoint.ll
===================================================================
--- llvm/test/Analysis/ScalarEvolution/ptrtoint.ll
+++ llvm/test/Analysis/ScalarEvolution/ptrtoint.ll
@@ -386,7 +386,7 @@
; X64-NEXT: %i9 = ptrtoint i8* %i7 to i64
; X64-NEXT: --> {(ptrtoint i8* %arg to i64),+,1}<nuw><%bb6> U: full-set S: full-set Exits: (-1 + (ptrtoint i8* %arg1 to i64)) LoopDispositions: { %bb6: Computable }
; X64-NEXT: %i10 = sub i64 %i9, %i4
-; X64-NEXT: --> {0,+,1}<nw><%bb6> U: full-set S: full-set Exits: (-1 + (-1 * (ptrtoint i8* %arg to i64)) + (ptrtoint i8* %arg1 to i64)) LoopDispositions: { %bb6: Computable }
+; X64-NEXT: --> {0,+,1}<nuw><%bb6> U: full-set S: full-set Exits: (-1 + (-1 * (ptrtoint i8* %arg to i64)) + (ptrtoint i8* %arg1 to i64)) LoopDispositions: { %bb6: Computable }
; X64-NEXT: %i11 = getelementptr inbounds i8, i8* %arg2, i64 %i10
; X64-NEXT: --> {%arg2,+,1}<nw><%bb6> U: full-set S: full-set Exits: (-1 + (-1 * (ptrtoint i8* %arg to i64)) + (ptrtoint i8* %arg1 to i64) + %arg2) LoopDispositions: { %bb6: Computable }
; X64-NEXT: %i12 = load i8, i8* %i11, align 1
@@ -413,7 +413,7 @@
; X32-NEXT: %i9 = ptrtoint i8* %i7 to i64
; X32-NEXT: --> {(zext i32 (ptrtoint i8* %arg to i32) to i64),+,1}<nuw><%bb6> U: [0,8589934591) S: [0,8589934591) Exits: ((zext i32 (-1 + (-1 * (ptrtoint i8* %arg to i32)) + (ptrtoint i8* %arg1 to i32)) to i64) + (zext i32 (ptrtoint i8* %arg to i32) to i64)) LoopDispositions: { %bb6: Computable }
; X32-NEXT: %i10 = sub i64 %i9, %i4
-; X32-NEXT: --> {0,+,1}<nw><%bb6> U: [0,4294967296) S: [0,4294967296) Exits: (zext i32 (-1 + (-1 * (ptrtoint i8* %arg to i32)) + (ptrtoint i8* %arg1 to i32)) to i64) LoopDispositions: { %bb6: Computable }
+; X32-NEXT: --> {0,+,1}<nuw><%bb6> U: [0,4294967296) S: [0,4294967296) Exits: (zext i32 (-1 + (-1 * (ptrtoint i8* %arg to i32)) + (ptrtoint i8* %arg1 to i32)) to i64) LoopDispositions: { %bb6: Computable }
; X32-NEXT: %i11 = getelementptr inbounds i8, i8* %arg2, i64 %i10
; X32-NEXT: --> {%arg2,+,1}<%bb6> U: full-set S: full-set Exits: (-1 + (-1 * (ptrtoint i8* %arg to i32)) + (ptrtoint i8* %arg1 to i32) + %arg2) LoopDispositions: { %bb6: Computable }
; X32-NEXT: %i12 = load i8, i8* %i11, align 1
@@ -471,7 +471,7 @@
; X64-NEXT: %i9 = ptrtoint i32* %i7 to i64
; X64-NEXT: --> {(ptrtoint i32* %arg to i64),+,4}<nuw><%bb6> U: full-set S: full-set Exits: ((4 * ((-4 + (-1 * (ptrtoint i32* %arg to i64)) + (ptrtoint i32* %arg1 to i64)) /u 4))<nuw> + (ptrtoint i32* %arg to i64)) LoopDispositions: { %bb6: Computable }
; X64-NEXT: %i10 = sub i64 %i9, %i4
-; X64-NEXT: --> {0,+,4}<nw><%bb6> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: (4 * ((-4 + (-1 * (ptrtoint i32* %arg to i64)) + (ptrtoint i32* %arg1 to i64)) /u 4))<nuw> LoopDispositions: { %bb6: Computable }
+; X64-NEXT: --> {0,+,4}<nuw><%bb6> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: (4 * ((-4 + (-1 * (ptrtoint i32* %arg to i64)) + (ptrtoint i32* %arg1 to i64)) /u 4))<nuw> LoopDispositions: { %bb6: Computable }
; X64-NEXT: %i11 = ashr exact i64 %i10, 2
; X64-NEXT: --> %i11 U: [-2305843009213693952,2305843009213693952) S: [-2305843009213693952,2305843009213693952) Exits: <<Unknown>> LoopDispositions: { %bb6: Variant }
; X64-NEXT: %i12 = getelementptr inbounds i32, i32* %arg2, i64 %i11
@@ -500,7 +500,7 @@
; X32-NEXT: %i9 = ptrtoint i32* %i7 to i64
; X32-NEXT: --> {(zext i32 (ptrtoint i32* %arg to i32) to i64),+,4}<nuw><%bb6> U: [0,8589934588) S: [0,8589934588) Exits: ((zext i32 (ptrtoint i32* %arg to i32) to i64) + (4 * ((zext i32 (-4 + (-1 * (ptrtoint i32* %arg to i32)) + (ptrtoint i32* %arg1 to i32)) to i64) /u 4))<nuw><nsw>) LoopDispositions: { %bb6: Computable }
; X32-NEXT: %i10 = sub i64 %i9, %i4
-; X32-NEXT: --> {0,+,4}<nw><%bb6> U: [0,4294967293) S: [0,4294967293) Exits: (4 * ((zext i32 (-4 + (-1 * (ptrtoint i32* %arg to i32)) + (ptrtoint i32* %arg1 to i32)) to i64) /u 4))<nuw><nsw> LoopDispositions: { %bb6: Computable }
+; X32-NEXT: --> {0,+,4}<nuw><%bb6> U: [0,4294967293) S: [0,4294967293) Exits: (4 * ((zext i32 (-4 + (-1 * (ptrtoint i32* %arg to i32)) + (ptrtoint i32* %arg1 to i32)) to i64) /u 4))<nuw><nsw> LoopDispositions: { %bb6: Computable }
; X32-NEXT: %i11 = ashr exact i64 %i10, 2
; X32-NEXT: --> %i11 U: [-2147483648,2147483648) S: [-2147483648,2147483648) Exits: <<Unknown>> LoopDispositions: { %bb6: Variant }
; X32-NEXT: %i12 = getelementptr inbounds i32, i32* %arg2, i64 %i11
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -2390,6 +2390,12 @@
}
}
+ // <0,+,any><nw> is also nuw
+ // TODO: Add corresponding nsw case
+ if (Type == scAddRecExpr && ScalarEvolution::hasFlags(Flags, SCEV::FlagNW) &&
+ !ScalarEvolution::hasFlags(Flags, SCEV::FlagNUW) && Ops[0]->isZero())
+ Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW);
+
return Flags;
}
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