This is an update to a previous commit (r181216).

The earlier change list introduced the following inst combines:
B * (uitofp i1 C) —> select C, B, 0
A * (1 - uitofp i1 C) —> select C, 0, A
select C, 0, B + select C, A, 0 —> select C, A, B

Together these 3 changes would simplify :
A * (1 - uitofp i1 C) + B * uitofp i1 C 
down to :
select C, B, A

In practice we found that the first two substitutions can have a
negative effect on performance, because they reduce opportunities to
use FMA contractions; between the two options FMAs are often the
better choice.  This change list amends the previous one to enable
just these inst combines:

select C, B, 0 + select C, 0, A —> select C, B, A
A * (1 - uitofp i1 C) + B * uitofp i1 C —> select C, B, A




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182499 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 56 insertions, 56 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 166f8dfdb4..a2c545f011 100644
--- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1262,6 +1262,49 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
     }
   }
 
+  // A * (1 - uitofp i1 C) + B * (uitofp i1 C) -> select C, B, A
+  {
+    if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
+      Value *M1L, *M1R, *M2L, *M2R;
+      if (match(LHS, m_FMul(m_Value(M1L), m_Value(M1R))) &&
+          match(RHS, m_FMul(m_Value(M2L), m_Value(M2R)))) {
+
+        Value *A, *B, *C1, *C2;
+        if (!match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))))
+          std::swap(M1L, M1R);
+        if (!match(M2R, m_UIToFp(m_Value(C2)))) 
+          std::swap(M2L, M2R);
+
+        if (match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))) &&
+            match(M2R, m_UIToFp(m_Value(C2))) &&
+            C2->getType()->isIntegerTy(1) &&
+            C1 == C2) {
+          A = M1L;
+          B = M2L;
+          return SelectInst::Create(C1, B, A);
+        }
+        
+        std::swap(M1L, M2L);
+        std::swap(M1R, M2R);
+        
+        if (!match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))))
+          std::swap(M1L, M1R);
+        if (!match(M2R, m_UIToFp(m_Value(C2)))) 
+          std::swap(M2L, M2R);
+
+        if (match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))) &&
+            match(M2R, m_UIToFp(m_Value(C2))) &&
+            C2->getType()->isIntegerTy(1) &&
+            C1 == C2) {
+          A = M1L;
+          B = M2L;
+          return SelectInst::Create(C1, B, A);
+        }
+      }
+    }
+  }
+
+  
   if (I.hasUnsafeAlgebra()) {
     if (Value *V = FAddCombine(Builder).simplify(&I))
       return ReplaceInstUsesWith(I, V);
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 51ca29bc07..2628f4b86b 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -524,35 +524,6 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
       }
     }
 
-    // B * (uitofp i1 C) -> select C, B, 0
-    if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
-      Value *LHS = Op0, *RHS = Op1;
-      Value *B, *C;
-      if (!match(RHS, m_UIToFp(m_Value(C))))
-        std::swap(LHS, RHS);
-
-      if (match(RHS, m_UIToFp(m_Value(C))) && C->getType()->isIntegerTy(1)) {
-        B = LHS;
-        Value *Zero = ConstantFP::getNegativeZero(B->getType());
-        return SelectInst::Create(C, B, Zero);
-      }
-    }
-
-    // A * (1 - uitofp i1 C) -> select C, 0, A
-    if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
-      Value *LHS = Op0, *RHS = Op1;
-      Value *A, *C;
-      if (!match(RHS, m_FSub(m_FPOne(), m_UIToFp(m_Value(C)))))
-        std::swap(LHS, RHS);
-
-      if (match(RHS, m_FSub(m_FPOne(), m_UIToFp(m_Value(C)))) &&
-          C->getType()->isIntegerTy(1)) {
-        A = LHS;
-        Value *Zero = ConstantFP::getNegativeZero(A->getType());
-        return SelectInst::Create(C, Zero, A);
-      }
-    }
-
     if (!isa<Constant>(Op1))
       std::swap(Opnd0, Opnd1);
     else
diff --git a/test/Transforms/InstCombine/add4.ll b/test/Transforms/InstCombine/add4.ll
index 0fc0a6c1ac..1047e162b5 100644
--- a/test/Transforms/InstCombine/add4.ll
+++ b/test/Transforms/InstCombine/add4.ll
@@ -6,30 +6,34 @@ target triple = "i686-apple-darwin8"
 
 define float @test1(float %A, float %B, i1 %C) {
 EntryBlock:
-  ;; A*(1 - uitofp i1 C) -> select C, 0, A
+  ;;  select C, 0, B + select C, A, 0 -> select C, A, B
   %cf = uitofp i1 %C to float
-  %mc = fsub float 1.000000e+00, %cf
-  %p1 = fmul fast float %A, %mc
-  ret float %p1
+  %s1 = select i1 %C, float 0.000000e+00, float %B
+  %s2 = select i1 %C, float %A, float 0.000000e+00
+  %sum = fadd fast float %s1, %s2
+  ret float %sum
 ; CHECK: @test1
-; CHECK: select i1 %C, float -0.000000e+00, float %A
+; CHECK: select i1 %C, float %A, float %B
 }
 
 define float @test2(float %A, float %B, i1 %C) {
 EntryBlock:
-  ;; B*(uitofp i1 C) -> select C, B, 0
+  ;;  B*(uitofp i1 C) + A*(1 - uitofp i1 C) -> select C, A, B
   %cf = uitofp i1 %C to float
+  %mc = fsub fast float 1.000000e+00, %cf
+  %p1 = fmul fast float %A, %mc
   %p2 = fmul fast float %B, %cf
-  ret float %p2
+  %s1 = fadd fast float %p2, %p1
+  ret float %s1
 ; CHECK: @test2
-; CHECK: select i1 %C, float %B, float -0.000000e+00
+; CHECK: select i1 %C, float %B, float %A
 }
 
 define float @test3(float %A, float %B, i1 %C) {
 EntryBlock:
   ;; A*(1 - uitofp i1 C) + B*(uitofp i1 C) -> select C, A, B
   %cf = uitofp i1 %C to float
-  %mc = fsub float 1.000000e+00, %cf
+  %mc = fsub fast float 1.000000e+00, %cf
   %p1 = fmul fast float %A, %mc
   %p2 = fmul fast float %B, %cf
   %s1 = fadd fast float %p1, %p2
@@ -38,21 +42,3 @@ EntryBlock:
 ; CHECK: select i1 %C, float %B, float %A
 }
 
-; PR15952
-define float @test4(float %A, float %B, i32 %C) {
-  %cf = uitofp i32 %C to float
-  %mc = fsub float 1.000000e+00, %cf
-  %p1 = fmul fast float %A, %mc
-  ret float %p1
-; CHECK: @test4
-; CHECK: uitofp
-}
-
-define float @test5(float %A, float %B, i32 %C) {
-  %cf = uitofp i32 %C to float
-  %p2 = fmul fast float %B, %cf
-  ret float %p2
-; CHECK: @test5
-; CHECK: uitofp
-}
-