[llvm] r221738 - [Reassociate] Canonicalize negative constants out of expressions.

[Chad Rosier]

Author: mcrosier
Date: Tue Nov 11 17:36:42 2014
New Revision: 221738

URL: http://llvm.org/viewvc/llvm-project?rev=221738&view=rev
Log:
[Reassociate] Canonicalize negative constants out of expressions.

Add support for FDiv, which was regressed by the previous commit.

Modified:
    llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
    llvm/trunk/test/Transforms/Reassociate/canonicalize-neg-const.ll

Modified: llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp?rev=221738&r1=221737&r2=221738&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp Tue Nov 11 17:36:42 2014
@@ -1955,7 +1955,8 @@ Instruction *Reassociate::canonicalizeNe
 
   // Must be a mul instruction.
   unsigned Opcode = I->getOpcode();
-  if (Opcode != Instruction::Mul && Opcode != Instruction::FMul)
+  if (Opcode != Instruction::Mul && Opcode != Instruction::FMul &&
+      Opcode != Instruction::FDiv)
     return nullptr;
 
   // Must have at least one constant operand.

Modified: llvm/trunk/test/Transforms/Reassociate/canonicalize-neg-const.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Reassociate/canonicalize-neg-const.ll?rev=221738&r1=221737&r2=221738&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/Reassociate/canonicalize-neg-const.ll (original)
+++ llvm/trunk/test/Transforms/Reassociate/canonicalize-neg-const.ll Tue Nov 11 17:36:42 2014
@@ -108,3 +108,51 @@ define double @test8(double %x, double %
   %add = fadd double %mul, %x
   ret double %add
 }
+
+; Canonicalize (x - -0.1234 / y)
+define double @test9(double %x, double %y) {
+; CHECK-LABEL: @test9
+; CHECK-NEXT: fdiv double 1.234000e-01, %y
+; CHECK-NEXT: fadd double %x, %div
+; CHECK-NEXT: ret double
+
+  %div = fdiv double -1.234000e-01, %y
+  %sub = fsub double %x, %div
+  ret double %sub
+}
+
+; Don't modify (-0.1234 / y - x)
+define double @test10(double %x, double %y) {
+; CHECK-LABEL: @test10
+; CHECK-NEXT: fdiv double -1.234000e-01, %y
+; CHECK-NEXT: fsub double %div, %x
+; CHECK-NEXT: ret double %sub
+
+  %div = fdiv double -1.234000e-01, %y
+  %sub = fsub double %div, %x
+  ret double %sub
+}
+
+; Canonicalize (-0.1234 / y + x) -> (x - 0.1234 / y)
+define double @test11(double %x, double %y) {
+; CHECK-LABEL: @test11
+; CHECK-NEXT: fdiv double 1.234000e-01, %y
+; CHECK-NEXT: fsub double %x, %div
+; CHECK-NEXT: ret double %add
+
+  %div = fdiv double -1.234000e-01, %y
+  %add = fadd double %div, %x
+  ret double %add
+}
+
+; Canonicalize (y / -0.1234 + x) -> (x - y / 0.1234)
+define double @test12(double %x, double %y) {
+; CHECK-LABEL: @test12
+; CHECK-NEXT: fdiv double %y, 1.234000e-01
+; CHECK-NEXT: fsub double %x, %div
+; CHECK-NEXT: ret double %add
+
+  %div = fdiv double %y, -1.234000e-01
+  %add = fadd double %div, %x
+  ret double %add
+}