AMDGPU: fix updating the alias rules since r340171

[hakzsam]

Summary

The two rules tables have to be updated because
MAX_COMMON_ADDRESS has been bumped to 6 for handling
32-bit constant address space. Otherwise, we might
have out of bounds access.

Reported by Jan Vesely.

[jvesely]

lib/Target/AMDGPU/AMDGPUAliasAnalysis.cpp

72

This does not match the current code. Is this a fixup for https://reviews.llvm.org/D47261?

afaik, MAX_COMMON_ADDRESS refers to address spaces shared between amdgcn and r600. r600 does not use CONST_32_BIT AS so it probably should not be in the table.
That said, bumping the table size does not impact r600, so renaming the MAX_COMMON_ADDRESS bound works as well.

[hakzsam]

lib/Target/AMDGPU/AMDGPUAliasAnalysis.cpp

72

Yes, you have to apply this https://reviews.llvm.org/D50973

I think so for MAX_COMMON_ADDRESS, so only ASAliasRulesGenIsZero should be updated?

[arsenm]

LGTM

[hakzsam]

In D50974#1206359, @arsenm wrote:

LGTM

Closed in favour of https://reviews.llvm.org/D47261

lib/Target/AMDGPU/AMDGPUAliasAnalysis.h

   private:
     Triple::ArchType Arch;
     AMDGPUAS AS;
-    const AliasResult (*ASAliasRules)[6][6];
+    const AliasResult (*ASAliasRules)[7][7];
   } ASAliasRules;
 };
 

lib/Target/AMDGPU/AMDGPUAliasAnalysis.cpp

 AMDGPUAAResult::ASAliasRulesTy::ASAliasRulesTy(AMDGPUAS AS_, Triple::ArchType Arch_)
   : Arch(Arch_), AS(AS_) {
   // These arrarys are indexed by address space value
-  // enum elements 0 ... to 5
-  static const AliasResult ASAliasRulesPrivIsZero[6][6] = {
-  /*             Private    Global    Constant  Group     Flat      Region*/
-  /* Private  */ {MayAlias, NoAlias , NoAlias , NoAlias , MayAlias, NoAlias},
-  /* Global   */ {NoAlias , MayAlias, MayAlias, NoAlias , MayAlias, NoAlias},
-  /* Constant */ {NoAlias , MayAlias, MayAlias, NoAlias , MayAlias, NoAlias},
-  /* Group    */ {NoAlias , NoAlias , NoAlias , MayAlias, MayAlias, NoAlias},
-  /* Flat     */ {MayAlias, MayAlias, MayAlias, MayAlias, MayAlias, MayAlias},
-  /* Region   */ {NoAlias , NoAlias , NoAlias , NoAlias , MayAlias, MayAlias}
+  // enum elements 0 ... to 6
+  static const AliasResult ASAliasRulesPrivIsZero[7][7] = {
+  /*                    Private    Global    Constant  Group     Flat      Region    Constant 32-bit */
+  /* Private  */        {MayAlias, NoAlias , NoAlias , NoAlias , MayAlias, NoAlias , NoAlias},
+  /* Global   */        {NoAlias , MayAlias, MayAlias, NoAlias , MayAlias, NoAlias , MayAlias},
+  /* Constant */        {NoAlias , MayAlias, MayAlias, NoAlias , MayAlias, NoAlias , MayAlias},
+  /* Group    */        {NoAlias , NoAlias , NoAlias , MayAlias, MayAlias, NoAlias , NoAlias},
+  /* Flat     */        {MayAlias, MayAlias, MayAlias, MayAlias, MayAlias, MayAlias, MayAlias},
+  /* Region   */        {NoAlias , NoAlias , NoAlias , NoAlias , MayAlias, MayAlias, NoAlias},
+  /* Constant 32-bit */ {NoAlias , MayAlias, MayAlias, NoAlias , MayAlias, NoAlias , MayAlias}
   };
-  static const AliasResult ASAliasRulesGenIsZero[6][6] = {
-  /*             Flat       Global    Region    Group     Constant  Private */
-  /* Flat     */ {MayAlias, MayAlias, MayAlias, MayAlias, MayAlias, MayAlias},
-  /* Global   */ {MayAlias, MayAlias, NoAlias , NoAlias , MayAlias, NoAlias},
-  /* Region   */ {MayAlias, NoAlias , NoAlias , NoAlias,  MayAlias, NoAlias},
-  /* Group    */ {MayAlias, NoAlias , NoAlias , MayAlias, NoAlias , NoAlias},
-  /* Constant */ {MayAlias, MayAlias, MayAlias, NoAlias , NoAlias,  NoAlias},
-  /* Private  */ {MayAlias, NoAlias , NoAlias , NoAlias , NoAlias , MayAlias}
+  static const AliasResult ASAliasRulesGenIsZero[7][7] = {
+  /*                    Flat       Global    Region    Group     Constant  Private   Constant 32-bit */
+  /* Flat     */        {MayAlias, MayAlias, MayAlias, MayAlias, MayAlias, MayAlias, MayAlias},
+  /* Global   */        {MayAlias, MayAlias, NoAlias , NoAlias , MayAlias, NoAlias , MayAlias},
+  /* Region   */        {MayAlias, NoAlias , NoAlias , NoAlias,  MayAlias, NoAlias , MayAlias},
+  /* Group    */        {MayAlias, NoAlias , NoAlias , MayAlias, NoAlias , NoAlias , NoAlias},
+  /* Constant */        {MayAlias, MayAlias, MayAlias, NoAlias , NoAlias,  NoAlias , MayAlias},
+  /* Private  */        {MayAlias, NoAlias , NoAlias , NoAlias , NoAlias , MayAlias, NoAlias},
+  /* Constant 32-bit */ {MayAlias, MayAlias, MayAlias, NoAlias , MayAlias, NoAlias , NoAlias}
   };
   static_assert(AMDGPUAS::MAX_COMMON_ADDRESS <= 6, "Addr space out of range");
   if (AS.FLAT_ADDRESS == 0) {
-    assert(AS.GLOBAL_ADDRESS   == 1 &&
-           AS.REGION_ADDRESS   == 2 &&
-           AS.LOCAL_ADDRESS    == 3 &&
-           AS.CONSTANT_ADDRESS == 4 &&
-           AS.PRIVATE_ADDRESS  == 5);
+    assert(AS.GLOBAL_ADDRESS         == 1 &&
+           AS.REGION_ADDRESS         == 2 &&
+           AS.LOCAL_ADDRESS          == 3 &&
+           AS.CONSTANT_ADDRESS       == 4 &&
+           AS.PRIVATE_ADDRESS        == 5 &&
+           AS.CONSTANT_ADDRESS_32BIT == 6);
     ASAliasRules = &ASAliasRulesGenIsZero;
   } else {
-    assert(AS.PRIVATE_ADDRESS  == 0 &&
-           AS.GLOBAL_ADDRESS   == 1 &&
-           AS.CONSTANT_ADDRESS == 2 &&
-           AS.LOCAL_ADDRESS    == 3 &&
-           AS.FLAT_ADDRESS     == 4 &&
-           AS.REGION_ADDRESS   == 5);
+    assert(AS.PRIVATE_ADDRESS        == 0 &&
+           AS.GLOBAL_ADDRESS         == 1 &&
+           AS.CONSTANT_ADDRESS       == 2 &&
+           AS.LOCAL_ADDRESS          == 3 &&
+           AS.FLAT_ADDRESS           == 4 &&
+           AS.REGION_ADDRESS         == 5 &&
+           AS.CONSTANT_ADDRESS_32BIT == 6);
     ASAliasRules = &ASAliasRulesPrivIsZero;
   }
 }

test/CodeGen/AMDGPU/amdgpu-alias-analysis.ll

   ret void
 }
 
-; CHECK: NoAlias:      i8 addrspace(1)* %p1, i8 addrspace(6)* %p
+; CHECK: MayAlias:      i8 addrspace(1)* %p1, i8 addrspace(6)* %p
 
-define void @test_32bit_addr_space(i8 addrspace(6)* %p, i8 addrspace(1)* %p1) {
+define void @test_constant_32bit_vs_global(i8 addrspace(6)* %p, i8 addrspace(1)* %p1) {
   ret void
 }
 

   ret void
 }
 
+; CHECK: MayAlias:      i8 addrspace(4)* %p1, i8 addrspace(6)* %p
+
+define void @test_constant_32bit_vs_constant(i8 addrspace(6)* %p, i8 addrspace(4)* %p1) {
+  ret void
+}
+