Rollup merge of rust-lang#48983 - gnzlbg:red, r=alexcrichton

add intrinsics for portable packed simd vector reductions

Adds the following portable vector reduction intrinsics:

* fn simd_reduce_add<T, U>(x: T) -> U;
* fn simd_reduce_mul<T, U>(x: T) -> U;
* fn simd_reduce_min<T, U>(x: T) -> U;
* fn simd_reduce_max<T, U>(x: T) -> U;
* fn simd_reduce_and<T, U>(x: T) -> U;
* fn simd_reduce_or<T, U>(x: T) -> U;
* fn simd_reduce_xor<T, U>(x: T) -> U;

I've also added:

* fn simd_reduce_all<T>(x: T) -> bool;
* fn simd_reduce_any<T>(x: T) -> bool;

These produce better code that what we are currently producing in `stdsimd`, but the code is still not optimal due to this LLVM bug:  https://bugs.llvm.org/show_bug.cgi?id=36702

r? @alexcrichton

Author: kennytm

Diff for: src/librustc_llvm/ffi.rs

@@ -621,6 +621,7 @@ extern "C" {
     pub fn LLVMConstIntGetSExtValue(ConstantVal: ValueRef) -> c_longlong;
     pub fn LLVMRustConstInt128Get(ConstantVal: ValueRef, SExt: bool,
                                   high: *mut u64, low: *mut u64) -> bool;
+    pub fn LLVMConstRealGetDouble (ConstantVal: ValueRef, losesInfo: *mut Bool) -> f64;
 
 
     // Operations on composite constants
@@ -1201,6 +1202,46 @@ extern "C" {
                                 Name: *const c_char)
                                 -> ValueRef;
 
+    pub fn LLVMRustBuildVectorReduceFAdd(B: BuilderRef,
+                                         Acc: ValueRef,
+                                         Src: ValueRef)
+                                         -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceFMul(B: BuilderRef,
+                                         Acc: ValueRef,
+                                         Src: ValueRef)
+                                         -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceAdd(B: BuilderRef,
+                                        Src: ValueRef)
+                                        -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceMul(B: BuilderRef,
+                                        Src: ValueRef)
+                                        -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceAnd(B: BuilderRef,
+                                        Src: ValueRef)
+                                        -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceOr(B: BuilderRef,
+                                       Src: ValueRef)
+                                       -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceXor(B: BuilderRef,
+                                        Src: ValueRef)
+                                        -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceMin(B: BuilderRef,
+                                        Src: ValueRef,
+                                        IsSigned: bool)
+                                        -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceMax(B: BuilderRef,
+                                        Src: ValueRef,
+                                        IsSigned: bool)
+                                        -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceFMin(B: BuilderRef,
+                                         Src: ValueRef,
+                                         IsNaN: bool)
+                                         -> ValueRef;
+    pub fn LLVMRustBuildVectorReduceFMax(B: BuilderRef,
+                                         Src: ValueRef,
+                                         IsNaN: bool)
+                                         -> ValueRef;
+
     pub fn LLVMBuildIsNull(B: BuilderRef, Val: ValueRef, Name: *const c_char) -> ValueRef;
     pub fn LLVMBuildIsNotNull(B: BuilderRef, Val: ValueRef, Name: *const c_char) -> ValueRef;
     pub fn LLVMBuildPtrDiff(B: BuilderRef,
@@ -1567,6 +1608,7 @@ extern "C" {
     pub fn LLVMRustWriteValueToString(value_ref: ValueRef, s: RustStringRef);
 
     pub fn LLVMIsAConstantInt(value_ref: ValueRef) -> ValueRef;
+    pub fn LLVMIsAConstantFP(value_ref: ValueRef) -> ValueRef;
 
     pub fn LLVMRustPassKind(Pass: PassRef) -> PassKind;
     pub fn LLVMRustFindAndCreatePass(Pass: *const c_char) -> PassRef;

Diff for: src/librustc_trans/builder.rs

@@ -955,6 +955,147 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         }
     }
 
+    pub fn vector_reduce_fadd_fast(&self, acc: ValueRef, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.fadd_fast");
+        unsafe {
+            // FIXME: add a non-fast math version once
+            // https://bugs.llvm.org/show_bug.cgi?id=36732
+            // is fixed.
+            let instr = llvm::LLVMRustBuildVectorReduceFAdd(self.llbuilder, acc, src);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceFAdd is not available in LLVM version < 5.0");
+            }
+            llvm::LLVMRustSetHasUnsafeAlgebra(instr);
+            instr
+        }
+    }
+    pub fn vector_reduce_fmul_fast(&self, acc: ValueRef, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.fmul_fast");
+        unsafe {
+            // FIXME: add a non-fast math version once
+            // https://bugs.llvm.org/show_bug.cgi?id=36732
+            // is fixed.
+            let instr = llvm::LLVMRustBuildVectorReduceFMul(self.llbuilder, acc, src);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceFMul is not available in LLVM version < 5.0");
+            }
+            llvm::LLVMRustSetHasUnsafeAlgebra(instr);
+            instr
+        }
+    }
+    pub fn vector_reduce_add(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.add");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceAdd(self.llbuilder, src);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceAdd is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+    pub fn vector_reduce_mul(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.mul");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceMul(self.llbuilder, src);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceMul is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+    pub fn vector_reduce_and(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.and");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceAnd(self.llbuilder, src);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceAnd is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+    pub fn vector_reduce_or(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.or");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceOr(self.llbuilder, src);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceOr is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+    pub fn vector_reduce_xor(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.xor");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceXor(self.llbuilder, src);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceXor is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+    pub fn vector_reduce_fmin(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.fmin");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceFMin(self.llbuilder, src, true);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceFMin is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+    pub fn vector_reduce_fmax(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.fmax");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceFMax(self.llbuilder, src, true);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceFMax is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+    pub fn vector_reduce_fmin_fast(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.fmin_fast");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceFMin(self.llbuilder, src, false);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceFMin is not available in LLVM version < 5.0");
+            }
+            llvm::LLVMRustSetHasUnsafeAlgebra(instr);
+            instr
+        }
+    }
+    pub fn vector_reduce_fmax_fast(&self, src: ValueRef) -> ValueRef {
+        self.count_insn("vector.reduce.fmax_fast");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceFMax(self.llbuilder, src, false);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceFMax is not available in LLVM version < 5.0");
+            }
+            llvm::LLVMRustSetHasUnsafeAlgebra(instr);
+            instr
+        }
+    }
+    pub fn vector_reduce_min(&self, src: ValueRef, is_signed: bool) -> ValueRef {
+        self.count_insn("vector.reduce.min");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceMin(self.llbuilder, src, is_signed);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceMin is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+    pub fn vector_reduce_max(&self, src: ValueRef, is_signed: bool) -> ValueRef {
+        self.count_insn("vector.reduce.max");
+        unsafe {
+            let instr = llvm::LLVMRustBuildVectorReduceMax(self.llbuilder, src, is_signed);
+            if instr.is_null() {
+                bug!("LLVMRustBuildVectorReduceMax is not available in LLVM version < 5.0");
+            }
+            instr
+        }
+    }
+
     pub fn extract_value(&self, agg_val: ValueRef, idx: u64) -> ValueRef {
         self.count_insn("extractvalue");
         assert_eq!(idx as c_uint as u64, idx);

Diff for: src/librustc_trans/common.rs

@@ -269,6 +269,19 @@ pub fn const_get_elt(v: ValueRef, idx: u64) -> ValueRef {
     }
 }
 
+pub fn const_get_real(v: ValueRef) -> Option<(f64, bool)> {
+    unsafe {
+        if is_const_real(v) {
+            let mut loses_info: llvm::Bool = ::std::mem::uninitialized();
+            let r = llvm::LLVMConstRealGetDouble(v, &mut loses_info as *mut llvm::Bool);
+            let loses_info = if loses_info == 1 { true } else { false };
+            Some((r, loses_info))
+        } else {
+            None
+        }
+    }
+}
+
 pub fn const_to_uint(v: ValueRef) -> u64 {
     unsafe {
         llvm::LLVMConstIntGetZExtValue(v)
@@ -281,6 +294,13 @@ pub fn is_const_integral(v: ValueRef) -> bool {
     }
 }
 
+pub fn is_const_real(v: ValueRef) -> bool {
+    unsafe {
+        !llvm::LLVMIsAConstantFP(v).is_null()
+    }
+}
+
+
 #[inline]
 fn hi_lo_to_u128(lo: u64, hi: u64) -> u128 {
     ((hi as u128) << 64) | (lo as u128)