compiler.cfg.value-numbering.comparisons: docs and tests

basis/compiler/cfg/value-numbering/comparisons/comarisons-docs.factor

@@ -0,0 +1,23 @@
+USING: compiler.cfg.instructions help.markup help.syntax kernel ;
+IN: compiler.cfg.value-numbering.comparisons
+
+HELP: >test-branch
+{ $values { "insn" insn } { "insn'" ##test-branch } }
+{ $description "Converts a " { $link ##compare-integer-imm-branch } " instruction into a " { $link ##test-branch } " instruction." } ;
+
+HELP: rewrite-into-test?
+{ $values { "insn" insn } { "?" boolean } }
+{ $description "Whether the comparison instruction can be rewritten into a test instruction." } ;
+
+ARTICLE: "compiler.cfg.value-numbering.comparisons" "Comparisons GVN"
+"Optimizations performed here:"
+$nl
+{ $list
+  "Eliminating intermediate boolean values when the result of a comparison is used by a compare-branch."
+  "Folding comparisons where both inputs are literal."
+  "Folding comparisons where both inputs are congruent."
+  "Converting compare instructions into compare-imm instructions."
+} ;
+
+
+ABOUT: "compiler.cfg.value-numbering.comparisons"

basis/compiler/cfg/value-numbering/comparisons/comparisons-tests.factor

@@ -0,0 +1,10 @@
+USING: compiler.cfg.comparisons compiler.cfg.instructions
+compiler.cfg.value-numbering.comparisons cpu.x86.assembler.operands
+kernel tools.test ;
+IN: compiler.cfg.value-numbering.comparisons.tests
+
+{
+    T{ ##test-branch { src1 RAX } { src2 RAX } { cc cc= } }
+} [
+    RAX 0 cc= f ##compare-integer-imm-branch boa >test-branch
+] unit-test

basis/compiler/cfg/value-numbering/comparisons/comparisons.factor

@@ -8,14 +8,6 @@ compiler.cfg.value-numbering.rewrite cpu.architecture kernel
 math math.order namespaces sequences vectors ;
 IN: compiler.cfg.value-numbering.comparisons
 
-! Optimizations performed here:
-!
-! 1) Eliminating intermediate boolean values when the result of
-! a comparison is used by a compare-branch
-! 2) Folding comparisons where both inputs are literal
-! 3) Folding comparisons where both inputs are congruent
-! 4) Converting compare instructions into compare-imm instructions
-
 : fold-compare-imm? ( insn -- ? )
     src1>> vreg>insn literal-insn? ;
 
@@ -101,7 +93,7 @@ UNION: general-compare-insn scalar-compare-insn ##test-vector ;
 : fold-compare-imm-branch ( insn -- insn/f )
     evaluate-compare-imm fold-branch ;
 
-: >test-branch ( insn -- insn )
+: >test-branch ( insn -- insn' )
     [ src1>> ] [ src1>> ] [ cc>> ] tri ##test-branch new-insn ;
 
 M: ##compare-imm-branch rewrite