[PATCH] D72979: [Codegen] Emit both AssumeAlignedAttr and AllocAlignAttr assumptions if they exist

[Roman Lebedev via Phabricator via cfe-commits]

lebedev.ri created this revision.
lebedev.ri added reviewers: erichkeane, jdoerfert, aaron.ballman.
lebedev.ri added a project: clang.
lebedev.ri edited the summary of this revision.

We shouldn't be just giving up if we find one of them
(like we currently do with `AssumeAlignedAttr`),
we should emit them all.

As the tests show, even if we materialized good knowledge
from `__attribute__((assume_aligned(32)`, it doesn't mean
`__attribute__((alloc_align([...])))` info won't be useful.
It might be, but that isn't given.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D72979

Files:
  clang/lib/CodeGen/CGCall.cpp
  clang/test/CodeGen/assume-aligned-and-alloc-align-attributes.c


Index: clang/test/CodeGen/assume-aligned-and-alloc-align-attributes.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/assume-aligned-and-alloc-align-attributes.c
@@ -0,0 +1,77 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | FileCheck %s
+
+void *my_aligned_alloc(int size, int alignment) __attribute__((assume_aligned(32), alloc_align(2)));
+
+// CHECK-LABEL: @t0_immediate0(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = call i8* @my_aligned_alloc(i32 320, i32 16)
+// CHECK-NEXT:    [[PTRINT:%.*]] = ptrtoint i8* [[CALL]] to i64
+// CHECK-NEXT:    [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 31
+// CHECK-NEXT:    [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND]])
+// CHECK-NEXT:    [[PTRINT1:%.*]] = ptrtoint i8* [[CALL]] to i64
+// CHECK-NEXT:    [[MASKEDPTR2:%.*]] = and i64 [[PTRINT1]], 15
+// CHECK-NEXT:    [[MASKCOND3:%.*]] = icmp eq i64 [[MASKEDPTR2]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND3]])
+// CHECK-NEXT:    ret i8* [[CALL]]
+//
+void *t0_immediate0() {
+  return my_aligned_alloc(320, 16);
+};
+
+// CHECK-LABEL: @t1_immediate1(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = call i8* @my_aligned_alloc(i32 320, i32 32)
+// CHECK-NEXT:    [[PTRINT:%.*]] = ptrtoint i8* [[CALL]] to i64
+// CHECK-NEXT:    [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 31
+// CHECK-NEXT:    [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND]])
+// CHECK-NEXT:    [[PTRINT1:%.*]] = ptrtoint i8* [[CALL]] to i64
+// CHECK-NEXT:    [[MASKEDPTR2:%.*]] = and i64 [[PTRINT1]], 31
+// CHECK-NEXT:    [[MASKCOND3:%.*]] = icmp eq i64 [[MASKEDPTR2]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND3]])
+// CHECK-NEXT:    ret i8* [[CALL]]
+//
+void *t1_immediate1() {
+  return my_aligned_alloc(320, 32);
+};
+
+// CHECK-LABEL: @t2_immediate2(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = call i8* @my_aligned_alloc(i32 320, i32 64)
+// CHECK-NEXT:    [[PTRINT:%.*]] = ptrtoint i8* [[CALL]] to i64
+// CHECK-NEXT:    [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 31
+// CHECK-NEXT:    [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND]])
+// CHECK-NEXT:    [[PTRINT1:%.*]] = ptrtoint i8* [[CALL]] to i64
+// CHECK-NEXT:    [[MASKEDPTR2:%.*]] = and i64 [[PTRINT1]], 63
+// CHECK-NEXT:    [[MASKCOND3:%.*]] = icmp eq i64 [[MASKEDPTR2]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND3]])
+// CHECK-NEXT:    ret i8* [[CALL]]
+//
+void *t2_immediate2() {
+  return my_aligned_alloc(320, 64);
+};
+
+// CHECK-LABEL: @t3_variable(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[ALIGNMENT_ADDR:%.*]] = alloca i32, align 4
+// CHECK-NEXT:    store i32 [[ALIGNMENT:%.*]], i32* [[ALIGNMENT_ADDR]], align 4
+// CHECK-NEXT:    [[TMP0:%.*]] = load i32, i32* [[ALIGNMENT_ADDR]], align 4
+// CHECK-NEXT:    [[CALL:%.*]] = call i8* @my_aligned_alloc(i32 320, i32 [[TMP0]])
+// CHECK-NEXT:    [[PTRINT:%.*]] = ptrtoint i8* [[CALL]] to i64
+// CHECK-NEXT:    [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 31
+// CHECK-NEXT:    [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND]])
+// CHECK-NEXT:    [[ALIGNMENTCAST:%.*]] = zext i32 [[TMP0]] to i64
+// CHECK-NEXT:    [[MASK:%.*]] = sub i64 [[ALIGNMENTCAST]], 1
+// CHECK-NEXT:    [[PTRINT1:%.*]] = ptrtoint i8* [[CALL]] to i64
+// CHECK-NEXT:    [[MASKEDPTR2:%.*]] = and i64 [[PTRINT1]], [[MASK]]
+// CHECK-NEXT:    [[MASKCOND3:%.*]] = icmp eq i64 [[MASKEDPTR2]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND3]])
+// CHECK-NEXT:    ret i8* [[CALL]]
+//
+void *t3_variable(int alignment) {
+  return my_aligned_alloc(320, alignment);
+};
Index: clang/lib/CodeGen/CGCall.cpp
===================================================================
--- clang/lib/CodeGen/CGCall.cpp
+++ clang/lib/CodeGen/CGCall.cpp
@@ -4629,7 +4629,8 @@
       llvm::ConstantInt *AlignmentCI = cast<llvm::ConstantInt>(Alignment);
       EmitAlignmentAssumption(Ret.getScalarVal(), RetTy, Loc, AA->getLocation(),
                               AlignmentCI, OffsetValue);
-    } else if (const auto *AA = TargetDecl->getAttr<AllocAlignAttr>()) {
+    }
+    if (const auto *AA = TargetDecl->getAttr<AllocAlignAttr>()) {
       llvm::Value *AlignmentVal = CallArgs[AA->getParamIndex().getLLVMIndex()]
                                       .getRValue(*this)
                                       .getScalarVal();


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