Fix more instances of dropped fast math flags when optimizing FADD instructions. All found by inspection (aka grep).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199528 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/InstCombine/fast-math.ll

@@ -160,6 +160,22 @@ define float @fold15(float %x, float %y) {
 ; CHECK: ret
 }
 
+; (select X+Y, X-Y) => X + (select Y, -Y)
+define float @fold16(float %x, float %y) {
+  %cmp = fcmp ogt float %x, %y
+  %plus = fadd fast float %x, %y
+  %minus = fsub fast float %x, %y
+  %r = select i1 %cmp, float %plus, float %minus
+  ret float %r
+; CHECK: fold16
+; CHECK: fsub fast float
+; CHECK: select
+; CHECK: fadd fast float
+; CHECK: ret
+}
+
+
+
 ; =========================================================================
 ;
 ;   Testing-cases about fmul begin

test/Transforms/InstCombine/fpcast.ll

@@ -31,6 +31,15 @@ define half @test4(float %a) {
   ret half %c
 }
 
+; CHECK: test4-fast
+define half @test4-fast(float %a) {
+; CHECK: fptrunc
+; CHECK: fsub fast
+  %b = fsub fast float -0.0, %a
+  %c = fptrunc float %b to half
+  ret half %c
+}
+
 ; CHECK: test5
 define half @test5(float %a, float %b, float %c) {
 ; CHECK: fcmp ogt