[llvm] [Analysis] Teach ScalarEvolution::getRangeRef about more dereferenceable objects (PR #104778)
David Sherwood via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 19 06:38:04 PDT 2024
https://github.com/david-arm created https://github.com/llvm/llvm-project/pull/104778
Whilst dealing with review comments on
https://github.com/llvm/llvm-project/pull/96752
I discovered that SCEV does not know about the dereferenceable attribute
on function arguments so I have updated getRangeRef to make use of it
by calling getPointerDereferenceableBytes.
>From aaec1d040ce48b0eab45678629200fc2f4f0499b Mon Sep 17 00:00:00 2001
From: David Sherwood <david.sherwood at arm.com>
Date: Mon, 19 Aug 2024 13:33:00 +0000
Subject: [PATCH] [Analysis] Teach ScalarEvolution::getRangeRef about more
dereferenceable objects
Whilst dealing with review comments on
https://github.com/llvm/llvm-project/pull/96752
I discovered that SCEV does not know about the dereferenceable
attribute on function arguments so I have updated getRangeRef
to make use of it by calling getPointerDereferenceableBytes.
---
llvm/lib/Analysis/ScalarEvolution.cpp | 7 +++----
.../ScalarEvolution/different-loops-recs.ll | 2 +-
.../ScalarEvolution/no-wrap-add-exprs.ll | 21 +++++++++++++++++--
3 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index a19358dee8ef49..88a201725f19b7 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6858,10 +6858,9 @@ const ConstantRange &ScalarEvolution::getRangeRef(
ObjectSizeOpts Opts;
Opts.RoundToAlign = false;
Opts.NullIsUnknownSize = true;
- uint64_t ObjSize;
- if ((isa<GlobalVariable>(V) || isa<AllocaInst>(V) ||
- isAllocationFn(V, &TLI)) &&
- getObjectSize(V, ObjSize, DL, &TLI, Opts) && ObjSize > 1) {
+ bool CanBeNull, CanBeFreed;
+ uint64_t ObjSize = V->getPointerDereferenceableBytes(DL, CanBeNull, CanBeFreed);
+ if (ObjSize > 1) {
// The highest address the object can start is ObjSize bytes before the
// end (unsigned max value). If this value is not a multiple of the
// alignment, the last possible start value is the next lowest multiple
diff --git a/llvm/test/Analysis/ScalarEvolution/different-loops-recs.ll b/llvm/test/Analysis/ScalarEvolution/different-loops-recs.ll
index 359e22fa41bacd..41e1d059803b21 100644
--- a/llvm/test/Analysis/ScalarEvolution/different-loops-recs.ll
+++ b/llvm/test/Analysis/ScalarEvolution/different-loops-recs.ll
@@ -457,7 +457,7 @@ define void @test_05(i32 %N) {
; CHECK-NEXT: %"alloca point" = bitcast i32 0 to i32
; CHECK-NEXT: --> 0 U: [0,1) S: [0,1)
; CHECK-NEXT: %tmp = getelementptr [1000 x i32], ptr @A, i32 0, i32 %i.0
-; CHECK-NEXT: --> {(8 + @A)<nuw><nsw>,+,4}<nw><%bb3> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: (408 + @A) LoopDispositions: { %bb3: Computable }
+; CHECK-NEXT: --> {(8 + @A)<nuw><nsw>,+,4}<nw><%bb3> U: [40,-3623) S: [-9223372036854775808,9223372036854775805) Exits: (408 + @A)<nuw> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: %tmp2 = add i32 %i.0, 1
; CHECK-NEXT: --> {3,+,1}<nuw><nsw><%bb3> U: [3,104) S: [3,104) Exits: 103 LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: %i.0 = phi i32 [ 2, %entry ], [ %tmp2, %bb ]
diff --git a/llvm/test/Analysis/ScalarEvolution/no-wrap-add-exprs.ll b/llvm/test/Analysis/ScalarEvolution/no-wrap-add-exprs.ll
index bd2ffddf396fe8..bb41a3dfc182fe 100644
--- a/llvm/test/Analysis/ScalarEvolution/no-wrap-add-exprs.ll
+++ b/llvm/test/Analysis/ScalarEvolution/no-wrap-add-exprs.ll
@@ -183,7 +183,7 @@ define void @f3(ptr %x_addr, ptr %y_addr, ptr %tmp_addr) {
; CHECK-NEXT: %s3.zext = zext i8 %s3 to i16
; CHECK-NEXT: --> (1 + (zext i8 (4 + (32 * %x) + (36 * %y)) to i16))<nuw><nsw> U: [1,254) S: [1,257)
; CHECK-NEXT: %ptr = bitcast ptr @z_addr to ptr
-; CHECK-NEXT: --> @z_addr U: [0,-3) S: [-9223372036854775808,9223372036854775805)
+; CHECK-NEXT: --> @z_addr U: [4,-19) S: [-9223372036854775808,9223372036854775805)
; CHECK-NEXT: %int0 = ptrtoint ptr %ptr to i32
; CHECK-NEXT: --> (trunc i64 (ptrtoint ptr @z_addr to i64) to i32) U: [0,-3) S: [-2147483648,2147483645)
; CHECK-NEXT: %int5 = add i32 %int0, 5
@@ -191,7 +191,7 @@ define void @f3(ptr %x_addr, ptr %y_addr, ptr %tmp_addr) {
; CHECK-NEXT: %int.zext = zext i32 %int5 to i64
; CHECK-NEXT: --> (1 + (zext i32 (4 + (trunc i64 (ptrtoint ptr @z_addr to i64) to i32)) to i64))<nuw><nsw> U: [1,4294967294) S: [1,4294967297)
; CHECK-NEXT: %ptr_noalign = bitcast ptr @z_addr_noalign to ptr
-; CHECK-NEXT: --> @z_addr_noalign U: full-set S: full-set
+; CHECK-NEXT: --> @z_addr_noalign U: [1,-16) S: full-set
; CHECK-NEXT: %int0_na = ptrtoint ptr %ptr_noalign to i32
; CHECK-NEXT: --> (trunc i64 (ptrtoint ptr @z_addr_noalign to i64) to i32) U: full-set S: full-set
; CHECK-NEXT: %int5_na = add i32 %int0_na, 5
@@ -362,3 +362,20 @@ loop:
exit2:
ret i1 false
}
+
+
+define void @dereferenceable_arg(ptr dereferenceable(128) %len_addr, ptr dereferenceable(128) align(8) %len_addr2) {
+; CHECK-LABEL: 'dereferenceable_arg'
+; CHECK-NEXT: Classifying expressions for: @dereferenceable_arg
+; CHECK-NEXT: %ptr = bitcast ptr %len_addr to ptr
+; CHECK-NEXT: --> %len_addr U: [1,-128) S: full-set
+; CHECK-NEXT: %ptr2 = bitcast ptr %len_addr2 to ptr
+; CHECK-NEXT: --> %len_addr2 U: [8,-135) S: [-9223372036854775808,9223372036854775801)
+; CHECK-NEXT: Determining loop execution counts for: @dereferenceable_arg
+;
+ entry:
+ %ptr = bitcast ptr %len_addr to ptr
+ %ptr2 = bitcast ptr %len_addr2 to ptr
+
+ ret void
+}
More information about the llvm-commits
mailing list