introduce and use ptradd/inbounds_ptradd instead of gep

Author: erikdesjardins

compiler/rustc_codegen_llvm/src/builder.rs

@@ -603,11 +603,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                 let llptr = if i == 0 {
                     place.llval
                 } else {
-                    self.inbounds_gep(
-                        self.type_i8(),
-                        place.llval,
-                        &[self.const_usize(b_offset.bytes())],
-                    )
+                    self.inbounds_ptradd(place.llval, self.const_usize(b_offset.bytes()))
                 };
                 let llty = place.layout.scalar_pair_element_llvm_type(self, i, false);
                 let load = self.load(llty, llptr, align);

compiler/rustc_codegen_llvm/src/va_arg.rs

@@ -44,12 +44,12 @@ fn emit_direct_ptr_va_arg<'ll, 'tcx>(
 
     let aligned_size = size.align_to(slot_size).bytes() as i32;
     let full_direct_size = bx.cx().const_i32(aligned_size);
-    let next = bx.inbounds_gep(bx.type_i8(), addr, &[full_direct_size]);
+    let next = bx.inbounds_ptradd(addr, full_direct_size);
     bx.store(next, va_list_addr, bx.tcx().data_layout.pointer_align.abi);
 
     if size.bytes() < slot_size.bytes() && bx.tcx().sess.target.endian == Endian::Big {
         let adjusted_size = bx.cx().const_i32((slot_size.bytes() - size.bytes()) as i32);
-        let adjusted = bx.inbounds_gep(bx.type_i8(), addr, &[adjusted_size]);
+        let adjusted = bx.inbounds_ptradd(addr, adjusted_size);
         (adjusted, addr_align)
     } else {
         (addr, addr_align)
@@ -109,14 +109,10 @@ fn emit_aapcs_va_arg<'ll, 'tcx>(
     // Table 3, Mapping of C & C++ built-in data types
     let ptr_offset = 8;
     let i32_offset = 4;
-    let gr_top = bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(ptr_offset)]);
-    let vr_top = bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(2 * ptr_offset)]);
-    let gr_offs = bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(3 * ptr_offset)]);
-    let vr_offs = bx.inbounds_gep(
-        bx.type_i8(),
-        va_list_addr,
-        &[bx.cx.const_usize(3 * ptr_offset + i32_offset)],
-    );
+    let gr_top = bx.inbounds_ptradd(va_list_addr, bx.cx.const_usize(ptr_offset));
+    let vr_top = bx.inbounds_ptradd(va_list_addr, bx.cx.const_usize(2 * ptr_offset));
+    let gr_offs = bx.inbounds_ptradd(va_list_addr, bx.cx.const_usize(3 * ptr_offset));
+    let vr_offs = bx.inbounds_ptradd(va_list_addr, bx.cx.const_usize(3 * ptr_offset + i32_offset));
 
     let layout = bx.cx.layout_of(target_ty);
 
@@ -164,11 +160,11 @@ fn emit_aapcs_va_arg<'ll, 'tcx>(
     let top = bx.load(top_type, reg_top, dl.pointer_align.abi);
 
     // reg_value = *(@top + reg_off_v);
-    let mut reg_addr = bx.gep(bx.type_i8(), top, &[reg_off_v]);
+    let mut reg_addr = bx.ptradd(top, reg_off_v);
     if bx.tcx().sess.target.endian == Endian::Big && layout.size.bytes() != slot_size {
         // On big-endian systems the value is right-aligned in its slot.
         let offset = bx.const_i32((slot_size - layout.size.bytes()) as i32);
-        reg_addr = bx.gep(bx.type_i8(), reg_addr, &[offset]);
+        reg_addr = bx.ptradd(reg_addr, offset);
     }
     let reg_type = layout.llvm_type(bx);
     let reg_value = bx.load(reg_type, reg_addr, layout.align.abi);
@@ -210,14 +206,10 @@ fn emit_s390x_va_arg<'ll, 'tcx>(
     let i64_offset = 8;
     let ptr_offset = 8;
     let gpr = va_list_addr;
-    let fpr = bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(i64_offset)]);
-    let overflow_arg_area =
-        bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(2 * i64_offset)]);
-    let reg_save_area = bx.inbounds_gep(
-        bx.type_i8(),
-        va_list_addr,
-        &[bx.cx.const_usize(2 * i64_offset + ptr_offset)],
-    );
+    let fpr = bx.inbounds_ptradd(va_list_addr, bx.cx.const_usize(i64_offset));
+    let overflow_arg_area = bx.inbounds_ptradd(va_list_addr, bx.cx.const_usize(2 * i64_offset));
+    let reg_save_area =
+        bx.inbounds_ptradd(va_list_addr, bx.cx.const_usize(2 * i64_offset + ptr_offset));
 
     let layout = bx.cx.layout_of(target_ty);
 
@@ -248,7 +240,7 @@ fn emit_s390x_va_arg<'ll, 'tcx>(
     let reg_ptr_v = bx.load(bx.type_ptr(), reg_save_area, dl.pointer_align.abi);
     let scaled_reg_count = bx.mul(reg_count_v, bx.const_u64(8));
     let reg_off = bx.add(scaled_reg_count, bx.const_u64(reg_save_index * 8 + reg_padding));
-    let reg_addr = bx.gep(bx.type_i8(), reg_ptr_v, &[reg_off]);
+    let reg_addr = bx.ptradd(reg_ptr_v, reg_off);
 
     // Update the register count.
     let new_reg_count_v = bx.add(reg_count_v, bx.const_u64(1));
@@ -262,11 +254,11 @@ fn emit_s390x_va_arg<'ll, 'tcx>(
     let arg_ptr_v =
         bx.load(bx.type_ptr(), overflow_arg_area, bx.tcx().data_layout.pointer_align.abi);
     let arg_off = bx.const_u64(padding);
-    let mem_addr = bx.gep(bx.type_i8(), arg_ptr_v, &[arg_off]);
+    let mem_addr = bx.ptradd(arg_ptr_v, arg_off);
 
     // Update the argument overflow area pointer.
     let arg_size = bx.cx().const_u64(padded_size);
-    let new_arg_ptr_v = bx.inbounds_gep(bx.type_i8(), arg_ptr_v, &[arg_size]);
+    let new_arg_ptr_v = bx.inbounds_ptradd(arg_ptr_v, arg_size);
     bx.store(new_arg_ptr_v, overflow_arg_area, dl.pointer_align.abi);
     bx.br(end);
 

compiler/rustc_codegen_ssa/src/mir/operand.rs

@@ -437,8 +437,7 @@ impl<'a, 'tcx, V: CodegenObject> OperandValue<V> {
                 let align = dest.align;
                 bx.store_with_flags(val, dest.llval, align, flags);
 
-                let llptr =
-                    bx.inbounds_gep(bx.type_i8(), dest.llval, &[bx.const_usize(b_offset.bytes())]);
+                let llptr = bx.inbounds_ptradd(dest.llval, bx.const_usize(b_offset.bytes()));
                 let val = bx.from_immediate(b);
                 let align = dest.align.restrict_for_offset(b_offset);
                 bx.store_with_flags(val, llptr, align, flags);
@@ -476,7 +475,7 @@ impl<'a, 'tcx, V: CodegenObject> OperandValue<V> {
         let address = bx.ptrtoint(alloca, bx.type_isize());
         let neg_address = bx.neg(address);
         let offset = bx.and(neg_address, align_minus_1);
-        let dst = bx.inbounds_gep(bx.type_i8(), alloca, &[offset]);
+        let dst = bx.inbounds_ptradd(alloca, offset);
         bx.memcpy(dst, min_align, llptr, min_align, size, MemFlags::empty());
 
         // Store the allocated region and the extra to the indirect place.

compiler/rustc_codegen_ssa/src/mir/place.rs

@@ -105,7 +105,7 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
             let llval = if offset.bytes() == 0 {
                 self.llval
             } else {
-                bx.inbounds_gep(bx.type_i8(), self.llval, &[bx.const_usize(offset.bytes())])
+                bx.inbounds_ptradd(self.llval, bx.const_usize(offset.bytes()))
             };
             PlaceRef {
                 llval,
@@ -164,7 +164,7 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
         debug!("struct_field_ptr: DST field offset: {:?}", offset);
 
         // Adjust pointer.
-        let ptr = bx.gep(bx.cx().type_i8(), self.llval, &[offset]);
+        let ptr = bx.ptradd(self.llval, offset);
 
         PlaceRef { llval: ptr, llextra: self.llextra, layout: field, align: effective_field_align }
     }

compiler/rustc_codegen_ssa/src/traits/builder.rs

@@ -190,6 +190,12 @@ pub trait BuilderMethods<'a, 'tcx>:
         ptr: Self::Value,
         indices: &[Self::Value],
     ) -> Self::Value;
+    fn ptradd(&mut self, ptr: Self::Value, offset: Self::Value) -> Self::Value {
+        self.gep(self.cx().type_i8(), ptr, &[offset])
+    }
+    fn inbounds_ptradd(&mut self, ptr: Self::Value, offset: Self::Value) -> Self::Value {
+        self.inbounds_gep(self.cx().type_i8(), ptr, &[offset])
+    }
 
     fn trunc(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value;
     fn sext(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value;