diff --git a/compiler/rustc_codegen_gcc/src/builder.rs b/compiler/rustc_codegen_gcc/src/builder.rs index b8e37b604801f..76846692459d5 100644 --- a/compiler/rustc_codegen_gcc/src/builder.rs +++ b/compiler/rustc_codegen_gcc/src/builder.rs @@ -1694,7 +1694,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> { fn to_immediate_scalar(&mut self, val: Self::Value, scalar: abi::Scalar) -> Self::Value { if scalar.is_bool() { - return self.trunc(val, self.cx().type_i1()); + return self.unchecked_utrunc(val, self.cx().type_i1()); } val } diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs index 57f09b1fa2fd2..4caa44b32dfa9 100644 --- a/compiler/rustc_codegen_llvm/src/builder.rs +++ b/compiler/rustc_codegen_llvm/src/builder.rs @@ -29,13 +29,13 @@ use smallvec::SmallVec; use tracing::{debug, instrument}; use crate::abi::FnAbiLlvmExt; -use crate::attributes; use crate::common::Funclet; use crate::context::{CodegenCx, SimpleCx}; use crate::llvm::{self, AtomicOrdering, AtomicRmwBinOp, BasicBlock, False, True}; use crate::type_::Type; use crate::type_of::LayoutLlvmExt; use crate::value::Value; +use crate::{attributes, llvm_util}; #[must_use] pub(crate) struct GenericBuilder<'a, 'll, CX: Borrow>> { @@ -562,7 +562,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> { fn to_immediate_scalar(&mut self, val: Self::Value, scalar: abi::Scalar) -> Self::Value { if scalar.is_bool() { - return self.trunc(val, self.cx().type_i1()); + return self.unchecked_utrunc(val, self.cx().type_i1()); } val } @@ -898,6 +898,30 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> { unsafe { llvm::LLVMBuildTrunc(self.llbuilder, val, dest_ty, UNNAMED) } } + fn unchecked_utrunc(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> &'ll Value { + let trunc = self.trunc(val, dest_ty); + if llvm_util::get_version() >= (19, 0, 0) { + unsafe { + if llvm::LLVMIsAInstruction(trunc).is_some() { + llvm::LLVMSetNUW(trunc, True); + } + } + } + trunc + } + + fn unchecked_strunc(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> &'ll Value { + let trunc = self.trunc(val, dest_ty); + if llvm_util::get_version() >= (19, 0, 0) { + unsafe { + if llvm::LLVMIsAInstruction(trunc).is_some() { + llvm::LLVMSetNSW(trunc, True); + } + } + } + trunc + } + fn sext(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> &'ll Value { unsafe { llvm::LLVMBuildSExt(self.llbuilder, val, dest_ty, UNNAMED) } } diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs index e800492dad02f..a989e9c64c0f9 100644 --- a/compiler/rustc_codegen_ssa/src/base.rs +++ b/compiler/rustc_codegen_ssa/src/base.rs @@ -24,7 +24,7 @@ use rustc_middle::query::Providers; use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutOf, TyAndLayout}; use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; use rustc_session::Session; -use rustc_session::config::{self, CrateType, EntryFnType, OptLevel, OutputType}; +use rustc_session::config::{self, CrateType, EntryFnType, OutputType}; use rustc_span::{DUMMY_SP, Symbol, sym}; use rustc_trait_selection::infer::{BoundRegionConversionTime, TyCtxtInferExt}; use rustc_trait_selection::traits::{ObligationCause, ObligationCtxt}; @@ -364,13 +364,7 @@ pub(crate) fn build_shift_expr_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( let rhs_sz = bx.cx().int_width(rhs_llty); let lhs_sz = bx.cx().int_width(lhs_llty); if lhs_sz < rhs_sz { - if is_unchecked && bx.sess().opts.optimize != OptLevel::No { - // FIXME: Use `trunc nuw` once that's available - let inrange = bx.icmp(IntPredicate::IntULE, rhs, mask); - bx.assume(inrange); - } - - bx.trunc(rhs, lhs_llty) + if is_unchecked { bx.unchecked_utrunc(rhs, lhs_llty) } else { bx.trunc(rhs, lhs_llty) } } else if lhs_sz > rhs_sz { // We zero-extend even if the RHS is signed. So e.g. `(x: i32) << -1i8` will zero-extend the // RHS to `255i32`. But then we mask the shift amount to be within the size of the LHS diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs index 2c843e2f5e460..f512e3e92f38d 100644 --- a/compiler/rustc_codegen_ssa/src/traits/builder.rs +++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs @@ -326,6 +326,17 @@ pub trait BuilderMethods<'a, 'tcx>: } fn trunc(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value; + /// Produces the same value as [`Self::trunc`] (and defaults to that), + /// but is UB unless the *zero*-extending the result can reproduce `val`. + fn unchecked_utrunc(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value { + self.trunc(val, dest_ty) + } + /// Produces the same value as [`Self::trunc`] (and defaults to that), + /// but is UB unless the *sign*-extending the result can reproduce `val`. + fn unchecked_strunc(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value { + self.trunc(val, dest_ty) + } + fn sext(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value; fn fptoui_sat(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value; fn fptosi_sat(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value; diff --git a/tests/codegen/intrinsics/transmute-niched.rs b/tests/codegen/intrinsics/transmute-niched.rs index 5ded0e192fa24..8ff5cc8ee4f4c 100644 --- a/tests/codegen/intrinsics/transmute-niched.rs +++ b/tests/codegen/intrinsics/transmute-niched.rs @@ -170,7 +170,7 @@ pub unsafe fn check_bool_from_ordering(x: std::cmp::Ordering) -> bool { // OPT: call void @llvm.assume(i1 %2) // CHECK-NOT: icmp // CHECK-NOT: assume - // CHECK: %[[R:.+]] = trunc i8 %x to i1 + // CHECK: %[[R:.+]] = trunc{{( nuw)?}} i8 %x to i1 // CHECK: ret i1 %[[R]] transmute(x) diff --git a/tests/codegen/intrinsics/transmute.rs b/tests/codegen/intrinsics/transmute.rs index 5b40a6a12c0fa..ff297b2706578 100644 --- a/tests/codegen/intrinsics/transmute.rs +++ b/tests/codegen/intrinsics/transmute.rs @@ -11,6 +11,9 @@ use std::intrinsics::mir::*; use std::intrinsics::{transmute, transmute_unchecked}; use std::mem::MaybeUninit; +// FIXME(LLVM18REMOVED): `trunc nuw` doesn't exist in LLVM 18, so once we no +// longer support it the optional flag checks can be changed to required. + pub enum ZstNever {} #[repr(align(2))] @@ -153,7 +156,7 @@ pub unsafe fn check_from_newtype(x: Scalar64) -> u64 { pub unsafe fn check_aggregate_to_bool(x: Aggregate8) -> bool { // CHECK: %x = alloca [1 x i8], align 1 // CHECK: %[[BYTE:.+]] = load i8, ptr %x, align 1 - // CHECK: %[[BOOL:.+]] = trunc i8 %[[BYTE]] to i1 + // CHECK: %[[BOOL:.+]] = trunc{{( nuw)?}} i8 %[[BYTE]] to i1 // CHECK: ret i1 %[[BOOL]] transmute(x) } @@ -171,7 +174,7 @@ pub unsafe fn check_aggregate_from_bool(x: bool) -> Aggregate8 { #[no_mangle] pub unsafe fn check_byte_to_bool(x: u8) -> bool { // CHECK-NOT: alloca - // CHECK: %[[R:.+]] = trunc i8 %x to i1 + // CHECK: %[[R:.+]] = trunc{{( nuw)?}} i8 %x to i1 // CHECK: ret i1 %[[R]] transmute(x) } @@ -284,7 +287,7 @@ pub unsafe fn check_long_array_more_aligned(x: [u8; 100]) -> [u32; 25] { #[no_mangle] pub unsafe fn check_pair_with_bool(x: (u8, bool)) -> (bool, i8) { // CHECK-NOT: alloca - // CHECK: trunc i8 %x.0 to i1 + // CHECK: trunc{{( nuw)?}} i8 %x.0 to i1 // CHECK: zext i1 %x.1 to i8 transmute(x) } @@ -338,7 +341,7 @@ pub unsafe fn check_heterogeneous_integer_pair(x: (i32, bool)) -> (bool, u32) { // CHECK: store i8 %[[WIDER]] // CHECK: %[[BYTE:.+]] = load i8 - // CHECK: trunc i8 %[[BYTE:.+]] to i1 + // CHECK: trunc{{( nuw)?}} i8 %[[BYTE:.+]] to i1 // CHECK: load i32 transmute(x) } diff --git a/tests/codegen/transmute-scalar.rs b/tests/codegen/transmute-scalar.rs index 43da7c1781ef3..c080259a9172e 100644 --- a/tests/codegen/transmute-scalar.rs +++ b/tests/codegen/transmute-scalar.rs @@ -26,7 +26,7 @@ pub fn bool_to_byte(b: bool) -> u8 { } // CHECK-LABEL: define{{.*}}zeroext i1 @byte_to_bool(i8{{.*}} %byte) -// CHECK: %_0 = trunc i8 %byte to i1 +// CHECK: %_0 = trunc{{( nuw)?}} i8 %byte to i1 // CHECK-NEXT: ret i1 %_0 #[no_mangle] pub unsafe fn byte_to_bool(byte: u8) -> bool { diff --git a/tests/codegen/unchecked_shifts.rs b/tests/codegen/unchecked_shifts.rs index b27eb73c0cc94..9fccaf2252e01 100644 --- a/tests/codegen/unchecked_shifts.rs +++ b/tests/codegen/unchecked_shifts.rs @@ -1,4 +1,10 @@ -//@ compile-flags: -Copt-level=3 +//@ revisions: LLVM18 LLVM19PLUS +//@ compile-flags: -Copt-level=3 -C no-prepopulate-passes +//@[LLVM18] exact-llvm-major-version: 18 +//@[LLVM19PLUS] min-llvm-version: 19 + +// This runs mir-opts to inline the standard library call, but doesn't run LLVM +// optimizations so it doesn't need to worry about them adding more flags. #![crate_type = "lib"] #![feature(unchecked_shifts)] @@ -17,13 +23,10 @@ pub unsafe fn unchecked_shl_unsigned_same(a: u32, b: u32) -> u32 { // CHECK-LABEL: @unchecked_shl_unsigned_smaller #[no_mangle] pub unsafe fn unchecked_shl_unsigned_smaller(a: u16, b: u32) -> u16 { - // This uses -DAG to avoid failing on irrelevant reorderings, - // like emitting the truncation earlier. - - // CHECK-DAG: %[[INRANGE:.+]] = icmp ult i32 %b, 16 - // CHECK-DAG: tail call void @llvm.assume(i1 %[[INRANGE]]) - // CHECK-DAG: %[[TRUNC:.+]] = trunc{{( nuw)?( nsw)?}} i32 %b to i16 - // CHECK-DAG: shl i16 %a, %[[TRUNC]] + // CHECK-NOT: assume + // LLVM18: %[[TRUNC:.+]] = trunc i32 %b to i16 + // LLVM19PLUS: %[[TRUNC:.+]] = trunc nuw i32 %b to i16 + // CHECK: shl i16 %a, %[[TRUNC]] a.unchecked_shl(b) } @@ -31,7 +34,7 @@ pub unsafe fn unchecked_shl_unsigned_smaller(a: u16, b: u32) -> u16 { #[no_mangle] pub unsafe fn unchecked_shl_unsigned_bigger(a: u64, b: u32) -> u64 { // CHECK-NOT: assume - // CHECK: %[[EXT:.+]] = zext{{( nneg)?}} i32 %b to i64 + // CHECK: %[[EXT:.+]] = zext i32 %b to i64 // CHECK: shl i64 %a, %[[EXT]] a.unchecked_shl(b) } @@ -49,13 +52,10 @@ pub unsafe fn unchecked_shr_signed_same(a: i32, b: u32) -> i32 { // CHECK-LABEL: @unchecked_shr_signed_smaller #[no_mangle] pub unsafe fn unchecked_shr_signed_smaller(a: i16, b: u32) -> i16 { - // This uses -DAG to avoid failing on irrelevant reorderings, - // like emitting the truncation earlier. - - // CHECK-DAG: %[[INRANGE:.+]] = icmp ult i32 %b, 16 - // CHECK-DAG: tail call void @llvm.assume(i1 %[[INRANGE]]) - // CHECK-DAG: %[[TRUNC:.+]] = trunc{{( nuw)?( nsw)?}} i32 %b to i16 - // CHECK-DAG: ashr i16 %a, %[[TRUNC]] + // CHECK-NOT: assume + // LLVM18: %[[TRUNC:.+]] = trunc i32 %b to i16 + // LLVM19PLUS: %[[TRUNC:.+]] = trunc nuw i32 %b to i16 + // CHECK: ashr i16 %a, %[[TRUNC]] a.unchecked_shr(b) } @@ -63,7 +63,7 @@ pub unsafe fn unchecked_shr_signed_smaller(a: i16, b: u32) -> i16 { #[no_mangle] pub unsafe fn unchecked_shr_signed_bigger(a: i64, b: u32) -> i64 { // CHECK-NOT: assume - // CHECK: %[[EXT:.+]] = zext{{( nneg)?}} i32 %b to i64 + // CHECK: %[[EXT:.+]] = zext i32 %b to i64 // CHECK: ashr i64 %a, %[[EXT]] a.unchecked_shr(b) } @@ -72,7 +72,7 @@ pub unsafe fn unchecked_shr_signed_bigger(a: i64, b: u32) -> i64 { #[no_mangle] pub unsafe fn unchecked_shr_u128_i8(a: u128, b: i8) -> u128 { // CHECK-NOT: assume - // CHECK: %[[EXT:.+]] = zext{{( nneg)?}} i8 %b to i128 + // CHECK: %[[EXT:.+]] = zext i8 %b to i128 // CHECK: lshr i128 %a, %[[EXT]] std::intrinsics::unchecked_shr(a, b) } @@ -81,7 +81,7 @@ pub unsafe fn unchecked_shr_u128_i8(a: u128, b: i8) -> u128 { #[no_mangle] pub unsafe fn unchecked_shl_i128_u8(a: i128, b: u8) -> i128 { // CHECK-NOT: assume - // CHECK: %[[EXT:.+]] = zext{{( nneg)?}} i8 %b to i128 + // CHECK: %[[EXT:.+]] = zext i8 %b to i128 // CHECK: shl i128 %a, %[[EXT]] std::intrinsics::unchecked_shl(a, b) } @@ -89,25 +89,19 @@ pub unsafe fn unchecked_shl_i128_u8(a: i128, b: u8) -> i128 { // CHECK-LABEL: @unchecked_shl_u8_i128 #[no_mangle] pub unsafe fn unchecked_shl_u8_i128(a: u8, b: i128) -> u8 { - // This uses -DAG to avoid failing on irrelevant reorderings, - // like emitting the truncation earlier. - - // CHECK-DAG: %[[INRANGE:.+]] = icmp ult i128 %b, 8 - // CHECK-DAG: tail call void @llvm.assume(i1 %[[INRANGE]]) - // CHECK-DAG: %[[TRUNC:.+]] = trunc{{( nuw)?( nsw)?}} i128 %b to i8 - // CHECK-DAG: shl i8 %a, %[[TRUNC]] + // CHECK-NOT: assume + // LLVM18: %[[TRUNC:.+]] = trunc i128 %b to i8 + // LLVM19PLUS: %[[TRUNC:.+]] = trunc nuw i128 %b to i8 + // CHECK: shl i8 %a, %[[TRUNC]] std::intrinsics::unchecked_shl(a, b) } // CHECK-LABEL: @unchecked_shr_i8_u128 #[no_mangle] pub unsafe fn unchecked_shr_i8_u128(a: i8, b: u128) -> i8 { - // This uses -DAG to avoid failing on irrelevant reorderings, - // like emitting the truncation earlier. - - // CHECK-DAG: %[[INRANGE:.+]] = icmp ult i128 %b, 8 - // CHECK-DAG: tail call void @llvm.assume(i1 %[[INRANGE]]) - // CHECK-DAG: %[[TRUNC:.+]] = trunc{{( nuw)?( nsw)?}} i128 %b to i8 - // CHECK-DAG: ashr i8 %a, %[[TRUNC]] + // CHECK-NOT: assume + // LLVM18: %[[TRUNC:.+]] = trunc i128 %b to i8 + // LLVM19PLUS: %[[TRUNC:.+]] = trunc nuw i128 %b to i8 + // CHECK: ashr i8 %a, %[[TRUNC]] std::intrinsics::unchecked_shr(a, b) } diff --git a/tests/codegen/union-abi.rs b/tests/codegen/union-abi.rs index 92d40d8ac14cb..ba98ab4fbdd53 100644 --- a/tests/codegen/union-abi.rs +++ b/tests/codegen/union-abi.rs @@ -136,4 +136,4 @@ pub union UnionBool { pub fn test_UnionBool(b: UnionBool) -> bool { unsafe { b.b } } -// CHECK: %_0 = trunc i8 %b to i1 +// CHECK: %_0 = trunc{{( nuw)?}} i8 %b to i1