[Clang][CodeGen] Stoping emitting alignment assumes for align_{up,down}

Now that `align_{up,down}` use `llvm.ptrmask` (as of #71238), the
assume doesn't preserve any information that is not still easily
re-computable.

Closes #71295

Author: goldsteinn

clang/lib/CodeGen/CGBuiltin.cpp

@@ -19696,10 +19696,6 @@ RValue CodeGenFunction::EmitBuiltinAlignTo(const CallExpr *E, bool AlignUp) {
     Result = Builder.CreateIntrinsic(
         Intrinsic::ptrmask, {Args.SrcType, Args.IntType},
         {SrcForMask, InvertedMask}, nullptr, "aligned_result");
-
-    // Emit an alignment assumption to ensure that the new alignment is
-    // propagated to loads/stores, etc.
-    emitAlignmentAssumption(Result, E, E->getExprLoc(), Args.Alignment);
   } else {
     Result = Builder.CreateAnd(SrcForMask, InvertedMask, "aligned_result");
   }

clang/test/CodeGen/builtin-align-array.c

@@ -9,12 +9,10 @@ extern int func(char *c);
 // CHECK-NEXT:    [[BUF:%.*]] = alloca [1024 x i8], align 16
 // CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [1024 x i8], ptr [[BUF]], i64 0, i64 44
 // CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[ARRAYIDX]], i64 -16)
-// CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[ALIGNED_RESULT]], i64 16) ]
 // CHECK-NEXT:    [[CALL:%.*]] = call i32 @func(ptr noundef [[ALIGNED_RESULT]])
 // CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds [1024 x i8], ptr [[BUF]], i64 0, i64 22
 // CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = getelementptr inbounds i8, ptr [[ARRAYIDX1]], i64 31
 // CHECK-NEXT:    [[ALIGNED_RESULT2:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[OVER_BOUNDARY]], i64 -32)
-// CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[ALIGNED_RESULT2]], i64 32) ]
 // CHECK-NEXT:    [[CALL3:%.*]] = call i32 @func(ptr noundef [[ALIGNED_RESULT2]])
 // CHECK-NEXT:    [[ARRAYIDX4:%.*]] = getelementptr inbounds [1024 x i8], ptr [[BUF]], i64 0, i64 16
 // CHECK-NEXT:    [[SRC_ADDR:%.*]] = ptrtoint ptr [[ARRAYIDX4]] to i64
@@ -35,12 +33,10 @@ int test_array(void) {
 // CHECK-NEXT:    [[BUF:%.*]] = alloca [1024 x i8], align 32
 // CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [1024 x i8], ptr [[BUF]], i64 0, i64 64
 // CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[ARRAYIDX]], i64 -16)
-// CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[ALIGNED_RESULT]], i64 16) ]
 // CHECK-NEXT:    [[CALL:%.*]] = call i32 @func(ptr noundef [[ALIGNED_RESULT]])
 // CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds [1024 x i8], ptr [[BUF]], i64 0, i64 32
 // CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = getelementptr inbounds i8, ptr [[ARRAYIDX1]], i64 31
 // CHECK-NEXT:    [[ALIGNED_RESULT2:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[OVER_BOUNDARY]], i64 -32)
-// CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[ALIGNED_RESULT2]], i64 32) ]
 // CHECK-NEXT:    [[CALL3:%.*]] = call i32 @func(ptr noundef [[ALIGNED_RESULT2]])
 // CHECK-NEXT:    ret i32 1
 //

clang/test/CodeGen/builtin-align.c

@@ -119,7 +119,6 @@ _Bool is_aligned(TYPE ptr, unsigned align) {
 // CHECK-VOID_PTR-NEXT:    [[OVER_BOUNDARY:%.*]] = getelementptr inbounds i8, ptr [[PTR:%.*]], i64 [[MASK]]
 // CHECK-VOID_PTR-NEXT:    [[INVERTED_MASK:%.*]] = xor i64 [[MASK]], -1
 // CHECK-VOID_PTR-NEXT:    [[ALIGNED_RESULT:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[OVER_BOUNDARY]], i64 [[INVERTED_MASK]])
-// CHECK-VOID_PTR-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[ALIGNED_RESULT]], i64 [[ALIGNMENT]]) ]
 // CHECK-VOID_PTR-NEXT:    ret ptr [[ALIGNED_RESULT]]
 //
 // CHECK-FLOAT_PTR-LABEL: define {{[^@]+}}@align_up
@@ -130,7 +129,6 @@ _Bool is_aligned(TYPE ptr, unsigned align) {
 // CHECK-FLOAT_PTR-NEXT:    [[OVER_BOUNDARY:%.*]] = getelementptr inbounds i8, ptr [[PTR:%.*]], i64 [[MASK]]
 // CHECK-FLOAT_PTR-NEXT:    [[INVERTED_MASK:%.*]] = xor i64 [[MASK]], -1
 // CHECK-FLOAT_PTR-NEXT:    [[ALIGNED_RESULT:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[OVER_BOUNDARY]], i64 [[INVERTED_MASK]])
-// CHECK-FLOAT_PTR-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[ALIGNED_RESULT]], i64 [[ALIGNMENT]]) ]
 // CHECK-FLOAT_PTR-NEXT:    ret ptr [[ALIGNED_RESULT]]
 //
 // CHECK-LONG-LABEL: define {{[^@]+}}@align_up
@@ -165,7 +163,6 @@ TYPE align_up(TYPE ptr, unsigned align) {
 // CHECK-VOID_PTR-NEXT:    [[MASK:%.*]] = sub i64 [[ALIGNMENT]], 1
 // CHECK-VOID_PTR-NEXT:    [[INVERTED_MASK:%.*]] = xor i64 [[MASK]], -1
 // CHECK-VOID_PTR-NEXT:    [[ALIGNED_RESULT:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[PTR:%.*]], i64 [[INVERTED_MASK]])
-// CHECK-VOID_PTR-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[ALIGNED_RESULT]], i64 [[ALIGNMENT]]) ]
 // CHECK-VOID_PTR-NEXT:    ret ptr [[ALIGNED_RESULT]]
 //
 // CHECK-FLOAT_PTR-LABEL: define {{[^@]+}}@align_down
@@ -175,7 +172,6 @@ TYPE align_up(TYPE ptr, unsigned align) {
 // CHECK-FLOAT_PTR-NEXT:    [[MASK:%.*]] = sub i64 [[ALIGNMENT]], 1
 // CHECK-FLOAT_PTR-NEXT:    [[INVERTED_MASK:%.*]] = xor i64 [[MASK]], -1
 // CHECK-FLOAT_PTR-NEXT:    [[ALIGNED_RESULT:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[PTR:%.*]], i64 [[INVERTED_MASK]])
-// CHECK-FLOAT_PTR-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[ALIGNED_RESULT]], i64 [[ALIGNMENT]]) ]
 // CHECK-FLOAT_PTR-NEXT:    ret ptr [[ALIGNED_RESULT]]
 //
 // CHECK-LONG-LABEL: define {{[^@]+}}@align_down