XXX: more

Author: nnethercote

compiler/rustc_codegen_ssa/src/base.rs

@@ -38,10 +38,11 @@ use rustc_span::symbol::sym;
 use rustc_span::Symbol;
 use rustc_target::abi::{Align, FIRST_VARIANT};
 
-use std::cmp;
 use std::collections::BTreeSet;
 use std::time::{Duration, Instant};
 
+use itertools::Itertools;
+
 pub fn bin_op_to_icmp_predicate(op: hir::BinOpKind, signed: bool) -> IntPredicate {
     match op {
         hir::BinOpKind::Eq => IntPredicate::IntEQ,
@@ -673,8 +674,10 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
     // are large size variations, this can reduce memory usage significantly.
     let codegen_units: Vec<_> = {
         let mut sorted_cgus = codegen_units.iter().collect::<Vec<_>>();
-        sorted_cgus.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate()));
-        sorted_cgus
+        sorted_cgus.sort_by_cached_key(|cgu| cgu.size_estimate());
+
+        let (first_half, second_half) = sorted_cgus.split_at(sorted_cgus.len() / 2);
+        second_half.iter().rev().interleave(first_half).copied().collect()
     };
 
     // Calculate the CGU reuse

compiler/rustc_monomorphize/src/partitioning.rs

@@ -313,7 +313,7 @@ fn merge_codegen_units<'tcx>(
     // worse generated code. So we don't allow CGUs smaller than this (unless
     // there is just one CGU, of course). Note that CGU sizes of 100,000+ are
     // common in larger programs, so this isn't all that large.
-    const NON_INCR_MIN_CGU_SIZE: usize = 1500;
+    const NON_INCR_MIN_CGU_SIZE: usize = 2000;
 
     // Repeatedly merge the two smallest codegen units as long as:
     // - we have more CGUs than the upper limit, or
@@ -353,9 +353,10 @@ fn merge_codegen_units<'tcx>(
                 //     codegen_units[codegen_units.len() - 1].size_estimate());
 
                 (codegen_units[0].size_estimate() as f64 * 0.8)
-                >= (codegen_units[codegen_units.len() - 2].size_estimate()
-                    + codegen_units[codegen_units.len() - 1].size_estimate()) as f64
-               };
+                    >= (codegen_units[codegen_units.len() - 2].size_estimate()
+                        + codegen_units[codegen_units.len() - 1].size_estimate())
+                        as f64
+            };
 
         if !(merge1 || merge2 || merge3) {
             break;