[Attributor] Deduce dereferenceable based on accessed bytes map

Summary:
This patch introduces the deduction based on load/store instructions whose pointer operand is a non-inbounds GEP instruction.
For example if we have,
```
void f(int *u){
 u[0] = 0;
 u[1] = 1;
 u[2] = 2;
}
```
then u must be dereferenceable(12).

This patch is inspired by D64258

Reviewers: jdoerfert, spatel, hfinkel, RKSimon, sstefan1, xbolva00, dtemirbulatov

Reviewed By: jdoerfert

Subscribers: jfb, lebedev.ri, xbolva00, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70714

1 files changed, 41 insertions, 2 deletions

diff --git a/llvm/test/Transforms/InferFunctionAttrs/dereferenceable.ll b/llvm/test/Transforms/InferFunctionAttrs/dereferenceable.ll
index bf7daba40d4..b6b699fac85 100644
--- a/llvm/test/Transforms/InferFunctionAttrs/dereferenceable.ll
+++ b/llvm/test/Transforms/InferFunctionAttrs/dereferenceable.ll
@@ -48,8 +48,7 @@ define double @PR21780_only_access3_without_inbounds(double* %ptr) {
 
 define double @PR21780_without_inbounds(double* %ptr) {
 ; CHECK-LABEL: @PR21780_without_inbounds(double* %ptr)
-; FIXME: this should be @PR21780_without_inbounds(double* nonnull dereferenceable(32) %ptr)
-; ATTRIBUTOR-LABEL: @PR21780_without_inbounds(double* nocapture nofree nonnull readonly align 8 dereferenceable(8) %ptr)
+; ATTRIBUTOR-LABEL: @PR21780_without_inbounds(double* nocapture nofree nonnull readonly align 8 dereferenceable(32) %ptr)
 
   %arrayidx1 = getelementptr double, double* %ptr, i64 1
   %arrayidx2 = getelementptr double, double* %ptr, i64 2
@@ -67,6 +66,7 @@ define double @PR21780_without_inbounds(double* %ptr) {
 
 define void @gep0(i8* %unused, i8* %other, i8* %ptr) {
 ; CHECK-LABEL: @gep0(i8* %unused, i8* %other, i8* %ptr)
+; ATTRIBUTOR-LABEL: @gep0(i8* nocapture nofree readnone %unused, i8* nocapture nofree nonnull writeonly dereferenceable(1) %other, i8* nocapture nofree nonnull readonly dereferenceable(3) %ptr)
   %arrayidx0 = getelementptr i8, i8* %ptr, i64 0
   %arrayidx1 = getelementptr i8, i8* %ptr, i64 1
   %arrayidx2 = getelementptr i8, i8* %ptr, i64 2
@@ -82,6 +82,7 @@ define void @gep0(i8* %unused, i8* %other, i8* %ptr) {
 
 define void @ordering(i8* %ptr1, i32* %ptr2) {
 ; CHECK-LABEL: @ordering(i8* %ptr1, i32* %ptr2)
+; ATTRIBUTOR-LABEL: @ordering(i8* nocapture nofree nonnull readonly dereferenceable(3) %ptr1, i32* nocapture nofree nonnull readonly dereferenceable(8) %ptr2)
   %a20 = getelementptr i32, i32* %ptr2, i64 0
   %a12 = getelementptr i8, i8* %ptr1, i64 2
   %t12 = load i8, i8* %a12
@@ -99,6 +100,7 @@ define void @ordering(i8* %ptr1, i32* %ptr2) {
 
 define void @not_entry_but_guaranteed_to_execute(i8* %ptr) {
 ; CHECK-LABEL: @not_entry_but_guaranteed_to_execute(i8* %ptr)
+; ATTRIBUTOR-LABEL: @not_entry_but_guaranteed_to_execute(i8* nocapture nofree nonnull readonly dereferenceable(3) %ptr)
 entry:
   br label %exit
 exit:
@@ -115,6 +117,7 @@ exit:
 
 define void @not_entry_not_guaranteed_to_execute(i8* %ptr, i1 %cond) {
 ; CHECK-LABEL: @not_entry_not_guaranteed_to_execute(i8* %ptr, i1 %cond)
+; ATTRIBUTOR-LABEL: @not_entry_not_guaranteed_to_execute(i8* nocapture nofree readonly %ptr, i1 %cond)
 entry:
   br i1 %cond, label %loads, label %exit
 loads:
@@ -133,6 +136,7 @@ exit:
 
 define void @partial_in_entry(i16* %ptr, i1 %cond) {
 ; CHECK-LABEL: @partial_in_entry(i16* %ptr, i1 %cond)
+; ATTRIBUTOR-LABEL: @partial_in_entry(i16* nocapture nofree nonnull readonly dereferenceable(4) %ptr, i1 %cond)
 entry:
   %arrayidx0 = getelementptr i16, i16* %ptr, i64 0
   %arrayidx1 = getelementptr i16, i16* %ptr, i64 1
@@ -152,6 +156,7 @@ exit:
 
 define void @volatile_is_not_dereferenceable(i16* %ptr) {
 ; CHECK-LABEL: @volatile_is_not_dereferenceable(i16* %ptr)
+; ATTRIBUTOR-LABEL: @volatile_is_not_dereferenceable(i16* nofree %ptr)
   %arrayidx0 = getelementptr i16, i16* %ptr, i64 0
   %arrayidx1 = getelementptr i16, i16* %ptr, i64 1
   %arrayidx2 = getelementptr i16, i16* %ptr, i64 2
@@ -165,6 +170,7 @@ define void @volatile_is_not_dereferenceable(i16* %ptr) {
 
 define void @atomic_is_alright(i16* %ptr) {
 ; CHECK-LABEL: @atomic_is_alright(i16* %ptr)
+; ATTRIBUTOR-LABEL: @atomic_is_alright(i16* nocapture nofree nonnull readonly align 2 dereferenceable(6) %ptr)
   %arrayidx0 = getelementptr i16, i16* %ptr, i64 0
   %arrayidx1 = getelementptr i16, i16* %ptr, i64 1
   %arrayidx2 = getelementptr i16, i16* %ptr, i64 2
@@ -178,6 +184,7 @@ declare void @may_not_return()
 
 define void @not_guaranteed_to_transfer_execution(i16* %ptr) {
 ; CHECK-LABEL: @not_guaranteed_to_transfer_execution(i16* %ptr)
+; ATTRIBUTOR-LABEL: @not_guaranteed_to_transfer_execution(i16* nocapture nonnull readonly dereferenceable(2) %ptr)
   %arrayidx0 = getelementptr i16, i16* %ptr, i64 0
   %arrayidx1 = getelementptr i16, i16* %ptr, i64 1
   %arrayidx2 = getelementptr i16, i16* %ptr, i64 2
@@ -192,6 +199,7 @@ define void @not_guaranteed_to_transfer_execution(i16* %ptr) {
 
 define void @variable_gep_index(i8* %unused, i8* %ptr, i64 %variable_index) {
 ; CHECK-LABEL: @variable_gep_index(i8* %unused, i8* %ptr, i64 %variable_index)
+; ATTRIBUTOR-LABEL: @variable_gep_index(i8* nocapture nofree readnone %unused, i8* nocapture nofree nonnull readonly dereferenceable(1) %ptr, i64 %variable_index)
   %arrayidx1 = getelementptr i8, i8* %ptr, i64 %variable_index
   %arrayidx2 = getelementptr i8, i8* %ptr, i64 2
   %t0 = load i8, i8* %ptr
@@ -204,6 +212,8 @@ define void @variable_gep_index(i8* %unused, i8* %ptr, i64 %variable_index) {
 
 define void @multi_index_gep(<4 x i8>* %ptr) {
 ; CHECK-LABEL: @multi_index_gep(<4 x i8>* %ptr)
+; FIXME: %ptr should be dereferenceable(4)
+; ATTRIBUTOR-LABEL: @multi_index_gep(<4 x i8>* nocapture nofree nonnull readonly dereferenceable(1) %ptr)
   %arrayidx00 = getelementptr <4 x i8>, <4 x i8>* %ptr, i64 0, i64 0
   %t0 = load i8, i8* %arrayidx00
   ret void
@@ -213,6 +223,7 @@ define void @multi_index_gep(<4 x i8>* %ptr) {
 
 define void @not_byte_multiple(i9* %ptr) {
 ; CHECK-LABEL: @not_byte_multiple(i9* %ptr)
+; ATTRIBUTOR-LABEL: @not_byte_multiple(i9* nocapture nofree nonnull readonly dereferenceable(2) %ptr) 
   %arrayidx0 = getelementptr i9, i9* %ptr, i64 0
   %t0 = load i9, i9* %arrayidx0
   ret void
@@ -222,6 +233,7 @@ define void @not_byte_multiple(i9* %ptr) {
 
 define void @no_pointer_deref(i16* %ptr) {
 ; CHECK-LABEL: @no_pointer_deref(i16* %ptr)
+; ATTRIBUTOR-LABEL: @no_pointer_deref(i16* nocapture nofree readonly %ptr)
   %arrayidx1 = getelementptr i16, i16* %ptr, i64 1
   %arrayidx2 = getelementptr i16, i16* %ptr, i64 2
   %t1 = load i16, i16* %arrayidx1
@@ -233,6 +245,7 @@ define void @no_pointer_deref(i16* %ptr) {
 
 define void @non_consecutive(i32* %ptr) {
 ; CHECK-LABEL: @non_consecutive(i32* %ptr)
+; ATTRIBUTOR-LABEL: @non_consecutive(i32* nocapture nofree nonnull readonly dereferenceable(8) %ptr)
   %arrayidx1 = getelementptr i32, i32* %ptr, i64 1
   %arrayidx0 = getelementptr i32, i32* %ptr, i64 0
   %arrayidx3 = getelementptr i32, i32* %ptr, i64 3
@@ -246,6 +259,7 @@ define void @non_consecutive(i32* %ptr) {
 
 define void @more_bytes(i32* dereferenceable(8) %ptr) {
 ; CHECK-LABEL: @more_bytes(i32* dereferenceable(8) %ptr)
+; ATTRIBUTOR-LABEL: @more_bytes(i32* nocapture nofree nonnull readonly dereferenceable(16) %ptr)
   %arrayidx3 = getelementptr i32, i32* %ptr, i64 3
   %arrayidx1 = getelementptr i32, i32* %ptr, i64 1
   %arrayidx0 = getelementptr i32, i32* %ptr, i64 0
@@ -261,6 +275,7 @@ define void @more_bytes(i32* dereferenceable(8) %ptr) {
 
 define void @more_bytes_and_not_null(i32* dereferenceable_or_null(8) %ptr) {
 ; CHECK-LABEL: @more_bytes_and_not_null(i32* dereferenceable_or_null(8) %ptr)
+; ATTRIBUTOR-LABEL: @more_bytes_and_not_null(i32* nocapture nofree nonnull readonly dereferenceable(16) %ptr)
   %arrayidx3 = getelementptr i32, i32* %ptr, i64 3
   %arrayidx1 = getelementptr i32, i32* %ptr, i64 1
   %arrayidx0 = getelementptr i32, i32* %ptr, i64 0
@@ -276,6 +291,7 @@ define void @more_bytes_and_not_null(i32* dereferenceable_or_null(8) %ptr) {
 
 define void @better_bytes(i32* dereferenceable(100) %ptr) {
 ; CHECK-LABEL: @better_bytes(i32* dereferenceable(100) %ptr)
+; ATTRIBUTOR-LABEL: @better_bytes(i32* nocapture nofree nonnull readonly dereferenceable(100) %ptr)
   %arrayidx3 = getelementptr i32, i32* %ptr, i64 3
   %arrayidx1 = getelementptr i32, i32* %ptr, i64 1
   %arrayidx0 = getelementptr i32, i32* %ptr, i64 0
@@ -289,6 +305,7 @@ define void @better_bytes(i32* dereferenceable(100) %ptr) {
 
 define void @bitcast(i32* %arg) {
 ; CHECK-LABEL: @bitcast(i32* %arg)
+; ATTRIBUTOR-LABEL: @bitcast(i32* nocapture nofree nonnull readonly dereferenceable(8) %arg)
   %ptr = bitcast i32* %arg to float*
   %arrayidx0 = getelementptr float, float* %ptr, i64 0
   %arrayidx1 = getelementptr float, float* %ptr, i64 1
@@ -299,6 +316,7 @@ define void @bitcast(i32* %arg) {
 
 define void @bitcast_different_sizes(double* %arg1, i8* %arg2) {
 ; CHECK-LABEL: @bitcast_different_sizes(double* %arg1, i8* %arg2)
+; ATTRIBUTOR-LABEL: @bitcast_different_sizes(double* nocapture nofree nonnull readonly dereferenceable(12) %arg1, i8* nocapture nofree nonnull readonly dereferenceable(16) %arg2)
   %ptr1 = bitcast double* %arg1 to float*
   %a10 = getelementptr float, float* %ptr1, i64 0
   %a11 = getelementptr float, float* %ptr1, i64 1
@@ -317,6 +335,7 @@ define void @bitcast_different_sizes(double* %arg1, i8* %arg2) {
 
 define void @negative_offset(i32* %arg) {
 ; CHECK-LABEL: @negative_offset(i32* %arg)
+; ATTRIBUTOR-LABEL: @negative_offset(i32* nocapture nofree nonnull readonly dereferenceable(4) %arg)
   %ptr = bitcast i32* %arg to float*
   %arrayidx0 = getelementptr float, float* %ptr, i64 0
   %arrayidx1 = getelementptr float, float* %ptr, i64 -1
@@ -327,6 +346,7 @@ define void @negative_offset(i32* %arg) {
 
 define void @stores(i32* %arg) {
 ; CHECK-LABEL: @stores(i32* %arg)
+; ATTRIBUTOR-LABEL: @stores(i32* nocapture nofree nonnull writeonly dereferenceable(8) %arg)
   %ptr = bitcast i32* %arg to float*
   %arrayidx0 = getelementptr float, float* %ptr, i64 0
   %arrayidx1 = getelementptr float, float* %ptr, i64 1
@@ -337,6 +357,7 @@ define void @stores(i32* %arg) {
 
 define void @load_store(i32* %arg) {
 ; CHECK-LABEL: @load_store(i32* %arg)
+; ATTRIBUTOR-LABEL: @load_store(i32* nocapture nofree nonnull dereferenceable(8) %arg)
   %ptr = bitcast i32* %arg to float*
   %arrayidx0 = getelementptr float, float* %ptr, i64 0
   %arrayidx1 = getelementptr float, float* %ptr, i64 1
@@ -344,3 +365,21 @@ define void @load_store(i32* %arg) {
   store float 2.0, float* %arrayidx1
   ret void
 }
+
+define void @different_size1(i32* %arg) {
+; CHECK-LABEL: @different_size1(i32* %arg)
+; ATTRIBUTOR-LABEL: @different_size1(i32* nocapture nofree nonnull writeonly dereferenceable(8) %arg)
+  %arg-cast = bitcast i32* %arg to double*
+  store double 0.000000e+00, double* %arg-cast
+  store i32 0, i32* %arg
+  ret void
+}
+
+define void @different_size2(i32* %arg) {
+; CHECK-LABEL: @different_size2(i32* %arg)
+; ATTRIBUTOR-LABEL: @different_size2(i32* nocapture nofree nonnull writeonly dereferenceable(8) %arg)
+  store i32 0, i32* %arg
+  %arg-cast = bitcast i32* %arg to double*
+  store double 0.000000e+00, double* %arg-cast
+  ret void
+}