Auto merge of rust-lang#105582 - saethlin:instcombine-assert-inhabited, r=cjgillot

InstCombine away intrinsic validity assertions

This optimization (currently) fires 246 times on the standard library. It seems to fire hardly at all on the big crates in the benchmark suite. Interesting.

Author: bors

src/intrinsics/mod.rs

@@ -21,6 +21,7 @@ mod simd;
 pub(crate) use cpuid::codegen_cpuid_call;
 pub(crate) use llvm::codegen_llvm_intrinsic_call;
 
+use rustc_middle::ty::layout::HasParamEnv;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_span::symbol::{kw, sym, Symbol};
@@ -659,7 +660,9 @@ fn codegen_regular_intrinsic_call<'tcx>(
                 return;
             }
 
-            if intrinsic == sym::assert_zero_valid && !fx.tcx.permits_zero_init(layout) {
+            if intrinsic == sym::assert_zero_valid
+                && !fx.tcx.permits_zero_init(fx.param_env().and(layout))
+            {
                 with_no_trimmed_paths!({
                     crate::base::codegen_panic(
                         fx,
@@ -674,7 +677,7 @@ fn codegen_regular_intrinsic_call<'tcx>(
             }
 
             if intrinsic == sym::assert_mem_uninitialized_valid
-                && !fx.tcx.permits_uninit_init(layout)
+                && !fx.tcx.permits_uninit_init(fx.param_env().and(layout))
             {
                 with_no_trimmed_paths!({
                     crate::base::codegen_panic(