File 0007-Fix-float-add-mul-reduction-codegen.patch of Package rust.14447

From 5c95f5fa6b6024ea0b8ed162e5d2c46c41aea1b0 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Sun, 7 Jul 2019 19:08:40 +0200
Subject: [PATCH] Fix float add/mul reduction codegen

The accumulator is now respected for unordered reductions.
Part of: Prepare for LLVM 9 update
https://github.com/rust-lang/rust/pull/62474
---
 src/librustc_codegen_llvm/common.rs       | 4 ++++
 src/librustc_codegen_llvm/intrinsic.rs    | 5 +++--
 src/librustc_codegen_llvm/llvm/ffi.rs     | 1 +
 src/librustc_codegen_ssa/traits/consts.rs | 1 +
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/librustc_codegen_llvm/common.rs b/src/librustc_codegen_llvm/common.rs
index 3b2701b893bb..e9f25e6344b0 100644
--- a/src/librustc_codegen_llvm/common.rs
+++ b/src/librustc_codegen_llvm/common.rs
@@ -249,6 +249,10 @@ impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         self.const_uint(self.type_i8(), i as u64)
     }
 
+    fn const_real(&self, t: &'ll Type, val: f64) -> &'ll Value {
+        unsafe { llvm::LLVMConstReal(t, val) }
+    }
+
     fn const_struct(
         &self,
         elts: &[&'ll Value],
diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs
index 69f8356f6692..dd6cfd7e29e4 100644
--- a/src/librustc_codegen_llvm/intrinsic.rs
+++ b/src/librustc_codegen_llvm/intrinsic.rs
@@ -1663,9 +1663,10 @@ fn generic_simd_intrinsic(
                             acc
                         } else {
                             // unordered arithmetic reductions do not:
+                            let identity_acc = if $name.contains("mul") { 1.0 } else { 0.0 };
                             match f.bit_width() {
-                                32 => bx.const_undef(bx.type_f32()),
-                                64 => bx.const_undef(bx.type_f64()),
+                                32 => bx.const_real(bx.type_f32(), identity_acc),
+                                64 => bx.const_real(bx.type_f64(), identity_acc),
                                 v => {
                                     return_error!(r#"
 unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
diff --git a/src/librustc_codegen_llvm/llvm/ffi.rs b/src/librustc_codegen_llvm/llvm/ffi.rs
index 75f639ec3eca..4bf0faa1ec32 100644
--- a/src/librustc_codegen_llvm/llvm/ffi.rs
+++ b/src/librustc_codegen_llvm/llvm/ffi.rs
@@ -715,6 +715,7 @@ extern "C" {
     // Operations on scalar constants
     pub fn LLVMConstInt(IntTy: &Type, N: c_ulonglong, SignExtend: Bool) -> &Value;
     pub fn LLVMConstIntOfArbitraryPrecision(IntTy: &Type, Wn: c_uint, Ws: *const u64) -> &Value;
+    pub fn LLVMConstReal(RealTy: &Type, N: f64) -> &Value;
     pub fn LLVMConstIntGetZExtValue(ConstantVal: &Value) -> c_ulonglong;
     pub fn LLVMRustConstInt128Get(ConstantVal: &Value, SExt: bool,
                                   high: &mut u64, low: &mut u64) -> bool;
diff --git a/src/librustc_codegen_ssa/traits/consts.rs b/src/librustc_codegen_ssa/traits/consts.rs
index 46286b5329e4..248fadfaf0f2 100644
--- a/src/librustc_codegen_ssa/traits/consts.rs
+++ b/src/librustc_codegen_ssa/traits/consts.rs
@@ -17,6 +17,7 @@ pub trait ConstMethods<'tcx>: BackendTypes {
     fn const_u64(&self, i: u64) -> Self::Value;
     fn const_usize(&self, i: u64) -> Self::Value;
     fn const_u8(&self, i: u8) -> Self::Value;
+    fn const_real(&self, t: Self::Type, val: f64) -> Self::Value;
 
     fn const_struct(&self, elts: &[Self::Value], packed: bool) -> Self::Value;