[FPEnv Core 11/14] Don't convert fpops to constexprs in SCCP

[sdmitrouk]

Flags rename.

[sdmitrouk]

Remove extra braces, use different overload of ConstantExpr::get().

[sdmitrouk]

Ping.

lib/Transforms/Scalar/SCCP.cpp

 // Handle Binary Operators.
 void SCCPSolver::visitBinaryOperator(Instruction &I) {
   LatticeVal V1State = getValueState(I.getOperand(0));
   LatticeVal V2State = getValueState(I.getOperand(1));
 
   LatticeVal &IV = ValueState[&I];
   if (IV.isOverdefined()) return;
 
-  if (V1State.isConstant() && V2State.isConstant())
-    return markConstant(IV, &I,
-                        ConstantExpr::get(I.getOpcode(), V1State.getConstant(),
-                                          V2State.getConstant()));
+  if (V1State.isConstant() && V2State.isConstant()) {
+    FastMathFlags FMF;
+
+    if (isa<FPMathOperator>(&I))
+      FMF = I.getFastMathFlags();
+
+    if (Constant *C = ConstantExpr::get(I.getOpcode(), V1State.getConstant(),
+                                        V2State.getConstant(), FMF,
+                                        /* Strict = */ true))
+      return markConstant(IV, &I, C);
+  }
 
   // If something is undef, wait for it to resolve.
   if (!V1State.isOverdefined() && !V2State.isOverdefined())
     return;
 
   // Otherwise, one of our operands is overdefined.  Try to produce something
   // better than overdefined with some tricks.
 

test/Transforms/SCCP/do-not-convert-fpop-to-constexpr.ll

+; fmuls shouldn't be converted to constant expressions.
+; RUN: opt < %s -sccp -S -enable-except-access-fp-math | FileCheck %s
+
+define double @do-not-convert-fpop-to-constexpr(double %x) {
+; CHECK-LABEL: @do-not-convert-fpop-to-constexpr(
+; CHECK: fmul
+; CHECK: fmul
+; CHECK-NOT: select
+entry:
+  %cmp = fcmp oeq double %x, 0.000000e+00
+  br i1 %cmp, label %cond.true, label %cond.false
+
+cond.true:
+  %val.true = fmul nrnd double 1.000000e+300, 1.000000e+300
+  br label %cond.end
+
+cond.false:
+  %val.false = fmul nrnd double 1.000000e-300, 1.000000e-300
+  br label %cond.end
+
+cond.end:
+  %cond = phi double [ %val.true, %cond.true ], [ %val.false, %cond.false ]
+  ret double %cond
+}