Rollup merge of #62801 - bjorn3:remove_lower_128bit_ops, r=alexcrichton

Remove support for -Zlower-128bit-ops

It is broken and unused

cc #58969

blocked rust-lang/compiler-builtins#302 (removes definitions of the lang items removed in this PR)

r? @alexcrichton

Author: Centril

Cargo.lock

@@ -17,7 +17,7 @@ dependencies = [
 name = "alloc"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_xorshift 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -110,7 +110,7 @@ dependencies = [
  "autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "backtrace-sys 0.1.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
@@ -122,7 +122,7 @@ version = "0.1.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -331,7 +331,7 @@ name = "cfg-if"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -460,7 +460,7 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.17"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -791,7 +791,7 @@ name = "dlmalloc"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -956,7 +956,7 @@ name = "fortanix-sgx-abi"
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -1133,7 +1133,7 @@ name = "hashbrown"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-alloc 1.0.0",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -1951,7 +1951,7 @@ dependencies = [
 name = "panic_abort"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1962,7 +1962,7 @@ version = "0.0.0"
 dependencies = [
  "alloc 0.0.0",
  "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "unwind 0.0.0",
@@ -2133,7 +2133,7 @@ name = "profiler_builtins"
 version = "0.0.0"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2670,7 +2670,7 @@ name = "rustc-demangle"
 version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -2762,7 +2762,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.38 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2984,7 +2984,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.38 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -3047,7 +3047,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.38 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -3165,7 +3165,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.38 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -3472,7 +3472,7 @@ dependencies = [
  "backtrace 0.3.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "dlmalloc 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fortanix-sgx-abi 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4099,7 +4099,7 @@ version = "0.0.0"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -4313,7 +4313,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum colored 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b0aa3473e85a3161b59845d6096b289bb577874cafeaf75ea1b1beaa6572c7fc"
 "checksum commoncrypto 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d056a8586ba25a1e4d61cb090900e495952c7886786fc55f909ab2f819b69007"
 "checksum commoncrypto-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1fed34f46747aa73dfaa578069fd8279d2818ade2b55f38f22a9401c7f4083e2"
-"checksum compiler_builtins 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)" = "ad9b4731b9e701aefe9e6bd1e9173f30526661508f9aaadaa5caec25ddf95585"
+"checksum compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)" = "ef1c086a06d6f52f9c0d50cacdc021bfb6034ddeec9fb7e62f099f13f65472f4"
 "checksum compiletest_rs 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)" = "f40ecc9332b68270998995c00f8051ee856121764a0d3230e64c9efd059d27b6"
 "checksum constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8ff012e225ce166d4422e0e78419d901719760f62ae2b7969ca6b564d1b54a9e"
 "checksum core-foundation 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4e2640d6d0bf22e82bed1b73c6aef8d5dd31e5abe6666c57e6d45e2649f4f887"

src/librustc/middle/lang_items.rs

@@ -367,34 +367,6 @@ language_item_table! {
 
     DebugTraitLangItem,          "debug_trait",        debug_trait,             Target::Trait;
 
-    // A lang item for each of the 128-bit operators we can optionally lower.
-    I128AddFnLangItem,           "i128_add",           i128_add_fn,             Target::Fn;
-    U128AddFnLangItem,           "u128_add",           u128_add_fn,             Target::Fn;
-    I128SubFnLangItem,           "i128_sub",           i128_sub_fn,             Target::Fn;
-    U128SubFnLangItem,           "u128_sub",           u128_sub_fn,             Target::Fn;
-    I128MulFnLangItem,           "i128_mul",           i128_mul_fn,             Target::Fn;
-    U128MulFnLangItem,           "u128_mul",           u128_mul_fn,             Target::Fn;
-    I128DivFnLangItem,           "i128_div",           i128_div_fn,             Target::Fn;
-    U128DivFnLangItem,           "u128_div",           u128_div_fn,             Target::Fn;
-    I128RemFnLangItem,           "i128_rem",           i128_rem_fn,             Target::Fn;
-    U128RemFnLangItem,           "u128_rem",           u128_rem_fn,             Target::Fn;
-    I128ShlFnLangItem,           "i128_shl",           i128_shl_fn,             Target::Fn;
-    U128ShlFnLangItem,           "u128_shl",           u128_shl_fn,             Target::Fn;
-    I128ShrFnLangItem,           "i128_shr",           i128_shr_fn,             Target::Fn;
-    U128ShrFnLangItem,           "u128_shr",           u128_shr_fn,             Target::Fn;
-    // And overflow versions for the operators that are checkable.
-    // While MIR calls these Checked*, they return (T,bool), not Option<T>.
-    I128AddoFnLangItem,          "i128_addo",          i128_addo_fn,            Target::Fn;
-    U128AddoFnLangItem,          "u128_addo",          u128_addo_fn,            Target::Fn;
-    I128SuboFnLangItem,          "i128_subo",          i128_subo_fn,            Target::Fn;
-    U128SuboFnLangItem,          "u128_subo",          u128_subo_fn,            Target::Fn;
-    I128MuloFnLangItem,          "i128_mulo",          i128_mulo_fn,            Target::Fn;
-    U128MuloFnLangItem,          "u128_mulo",          u128_mulo_fn,            Target::Fn;
-    I128ShloFnLangItem,          "i128_shlo",          i128_shlo_fn,            Target::Fn;
-    U128ShloFnLangItem,          "u128_shlo",          u128_shlo_fn,            Target::Fn;
-    I128ShroFnLangItem,          "i128_shro",          i128_shro_fn,            Target::Fn;
-    U128ShroFnLangItem,          "u128_shro",          u128_shro_fn,            Target::Fn;
-
     // Align offset for stride != 1, must not panic.
     AlignOffsetLangItem,         "align_offset",       align_offset_fn,         Target::Fn;
 

src/librustc/session/config.rs

@@ -1406,10 +1406,6 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
     saturating_float_casts: bool = (false, parse_bool, [TRACKED],
         "make float->int casts UB-free: numbers outside the integer type's range are clipped to \
          the max/min integer respectively, and NaN is mapped to 0"),
-    lower_128bit_ops: Option<bool> = (None, parse_opt_bool, [TRACKED],
-        "rewrite operators on i128 and u128 into lang item calls (typically provided \
-         by compiler-builtins) so codegen doesn't need to support them,
-         overriding the default for the current target"),
     human_readable_cgu_names: bool = (false, parse_bool, [TRACKED],
         "generate human-readable, predictable names for codegen units"),
     dep_info_omit_d_target: bool = (false, parse_bool, [TRACKED],

src/librustc/ty/context.rs

@@ -21,7 +21,7 @@ use crate::middle::cstore::EncodedMetadata;
 use crate::middle::lang_items;
 use crate::middle::resolve_lifetime::{self, ObjectLifetimeDefault};
 use crate::middle::stability;
-use crate::mir::{self, Body, interpret, ProjectionKind};
+use crate::mir::{Body, interpret, ProjectionKind};
 use crate::mir::interpret::{ConstValue, Allocation, Scalar};
 use crate::ty::subst::{Kind, InternalSubsts, SubstsRef, Subst};
 use crate::ty::ReprOptions;
@@ -1297,40 +1297,6 @@ impl<'tcx> TyCtxt<'tcx> {
         self.get_lang_items(LOCAL_CRATE)
     }
 
-    /// Due to missing llvm support for lowering 128 bit math to software emulation
-    /// (on some targets), the lowering can be done in MIR.
-    ///
-    /// This function only exists until said support is implemented.
-    pub fn is_binop_lang_item(&self, def_id: DefId) -> Option<(mir::BinOp, bool)> {
-        let items = self.lang_items();
-        let def_id = Some(def_id);
-        if items.i128_add_fn() == def_id { Some((mir::BinOp::Add, false)) }
-        else if items.u128_add_fn() == def_id { Some((mir::BinOp::Add, false)) }
-        else if items.i128_sub_fn() == def_id { Some((mir::BinOp::Sub, false)) }
-        else if items.u128_sub_fn() == def_id { Some((mir::BinOp::Sub, false)) }
-        else if items.i128_mul_fn() == def_id { Some((mir::BinOp::Mul, false)) }
-        else if items.u128_mul_fn() == def_id { Some((mir::BinOp::Mul, false)) }
-        else if items.i128_div_fn() == def_id { Some((mir::BinOp::Div, false)) }
-        else if items.u128_div_fn() == def_id { Some((mir::BinOp::Div, false)) }
-        else if items.i128_rem_fn() == def_id { Some((mir::BinOp::Rem, false)) }
-        else if items.u128_rem_fn() == def_id { Some((mir::BinOp::Rem, false)) }
-        else if items.i128_shl_fn() == def_id { Some((mir::BinOp::Shl, false)) }
-        else if items.u128_shl_fn() == def_id { Some((mir::BinOp::Shl, false)) }
-        else if items.i128_shr_fn() == def_id { Some((mir::BinOp::Shr, false)) }
-        else if items.u128_shr_fn() == def_id { Some((mir::BinOp::Shr, false)) }
-        else if items.i128_addo_fn() == def_id { Some((mir::BinOp::Add, true)) }
-        else if items.u128_addo_fn() == def_id { Some((mir::BinOp::Add, true)) }
-        else if items.i128_subo_fn() == def_id { Some((mir::BinOp::Sub, true)) }
-        else if items.u128_subo_fn() == def_id { Some((mir::BinOp::Sub, true)) }
-        else if items.i128_mulo_fn() == def_id { Some((mir::BinOp::Mul, true)) }
-        else if items.u128_mulo_fn() == def_id { Some((mir::BinOp::Mul, true)) }
-        else if items.i128_shlo_fn() == def_id { Some((mir::BinOp::Shl, true)) }
-        else if items.u128_shlo_fn() == def_id { Some((mir::BinOp::Shl, true)) }
-        else if items.i128_shro_fn() == def_id { Some((mir::BinOp::Shr, true)) }
-        else if items.u128_shro_fn() == def_id { Some((mir::BinOp::Shr, true)) }
-        else { None }
-    }
-
     pub fn stability(self) -> &'tcx stability::Index<'tcx> {
         self.stability_index(LOCAL_CRATE)
     }

src/librustc_mir/interpret/intrinsics.rs

@@ -230,21 +230,10 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         &mut self,
         instance: ty::Instance<'tcx>,
         args: &[OpTy<'tcx, M::PointerTag>],
-        dest: Option<PlaceTy<'tcx, M::PointerTag>>,
+        _dest: Option<PlaceTy<'tcx, M::PointerTag>>,
     ) -> InterpResult<'tcx, bool> {
         let def_id = instance.def_id();
-        // Some fn calls are actually BinOp intrinsics
-        if let Some((op, oflo)) = self.tcx.is_binop_lang_item(def_id) {
-            let dest = dest.expect("128 lowerings can't diverge");
-            let l = self.read_immediate(args[0])?;
-            let r = self.read_immediate(args[1])?;
-            if oflo {
-                self.binop_with_overflow(op, l, r, dest)?;
-            } else {
-                self.binop_ignore_overflow(op, l, r, dest)?;
-            }
-            return Ok(true);
-        } else if Some(def_id) == self.tcx.lang_items().panic_fn() {
+        if Some(def_id) == self.tcx.lang_items().panic_fn() {
             assert!(args.len() == 1);
             // &(&'static str, &'static str, u32, u32)
             let place = self.deref_operand(args[0])?;

src/librustc_mir/transform/inline.rs

@@ -232,13 +232,6 @@ impl Inliner<'tcx> {
             return false;
         }
 
-        // Do not inline {u,i}128 lang items, codegen const eval depends
-        // on detecting calls to these lang items and intercepting them
-        if tcx.is_binop_lang_item(callsite.callee).is_some() {
-            debug!("    not inlining 128bit integer lang item");
-            return false;
-        }
-
         let codegen_fn_attrs = tcx.codegen_fn_attrs(callsite.callee);
 
         let hinted = match codegen_fn_attrs.inline {