From: Chad Rosier <mcrosier@codeaurora.org>
Date: Tue, 11 Nov 2014 23:36:42 +0000 (+0000)
Subject: [Reassociate] Canonicalize negative constants out of expressions.
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=7ad8db4cbbfa879ac1a7bdd71ebfa84cab5df2ef;p=oota-llvm.git

[Reassociate] Canonicalize negative constants out of expressions.

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221738 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/Reassociate.cpp b/lib/Transforms/Scalar/Reassociate.cpp
index 7cde3ab6be8..a24d3d454f6 100644
--- a/lib/Transforms/Scalar/Reassociate.cpp
+++ b/lib/Transforms/Scalar/Reassociate.cpp
@@ -1955,7 +1955,8 @@ Instruction *Reassociate::canonicalizeNegConstExpr(Instruction *I) {
 
   // 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.
diff --git a/test/Transforms/Reassociate/canonicalize-neg-const.ll b/test/Transforms/Reassociate/canonicalize-neg-const.ll
index 5ac8a1f2694..80f433a498d 100644
--- a/test/Transforms/Reassociate/canonicalize-neg-const.ll
+++ b/test/Transforms/Reassociate/canonicalize-neg-const.ll
@@ -108,3 +108,51 @@ define double @test8(double %x, double %y) {
   %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
+}