[PATCH] D82034: [docs] Clarify semantics of ordered fadd/fmul reductions.

[Amara Emerson via Phabricator via llvm-commits]

aemerson updated this revision to Diff 271501.
aemerson retitled this revision from "[docs] Clarify semantics of ordered fadd reductions." to "[docs] Clarify semantics of ordered fadd/fmul reductions.".

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D82034/new/

https://reviews.llvm.org/D82034

Files:
  llvm/docs/LangRef.rst


Index: llvm/docs/LangRef.rst
===================================================================
--- llvm/docs/LangRef.rst
+++ llvm/docs/LangRef.rst
@@ -15131,7 +15131,17 @@
 If the intrinsic call has the 'reassoc' or 'fast' flags set, then the
 reduction will not preserve the associativity of an equivalent scalarized
 counterpart. Otherwise the reduction will be *ordered*, thus implying that
-the operation respects the associativity of a scalarized reduction.
+the operation respects the associativity of a scalarized reduction. That is, the
+reduction begins with the start value, and performs an fadd operation with consecutively
+increasing vector element indices. See the following pseudocode:
+
+::
+
+    float ordered_fadd(start_value, input_vector)
+      result = start_value
+      for i = 0 to length(input_vector)
+        result = result + input_vector[i]
+      return result
 
 
 Arguments:
@@ -15192,7 +15202,17 @@
 If the intrinsic call has the 'reassoc' or 'fast' flags set, then the
 reduction will not preserve the associativity of an equivalent scalarized
 counterpart. Otherwise the reduction will be *ordered*, thus implying that
-the operation respects the associativity of a scalarized reduction.
+the operation respects the associativity of a scalarized reduction. That is, the
+reduction begins with the start value, and performs an fmul operation with consecutively
+increasing vector element indices. See the following pseudocode:
+
+::
+
+    float ordered_fmul(start_value, input_vector)
+      result = start_value
+      for i = 0 to length(input_vector)
+        result = result * input_vector[i]
+      return result
 
 
 Arguments:


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