SpeculativeExecution: Allow speculating compares

[arsenm]

Merged with other patch

lib/Transforms/Scalar/SpeculativeExecution.cpp

switch (Operator::getOpcode(I)) {
     case Instruction::SIToFP:
     case Instruction::FPExt:
     case Instruction::FPTrunc:
     case Instruction::FAdd:
     case Instruction::FSub:
     case Instruction::FMul:
     case Instruction::FDiv:
     case Instruction::FRem:
+    case Instruction::ICmp:
+    case Instruction::FCmp:
       return TTI.getUserCost(I);
 
     default:
       return UINT_MAX; // Disallow anything not whitelisted.
   }
 }
 
 bool SpeculativeExecutionPass::considerHoistingFromTo(

test/Transforms/SpeculativeExecution/spec-compares.ll

+; RUN: opt < %s -S -speculative-execution \
+; RUN:   -spec-exec-max-speculation-cost 4 -spec-exec-max-not-hoisted 3 \
+; RUN:   | FileCheck %s
+
+; CHECK-LABEL: @ifThen_icmp(
+; CHECK: icmp
+; CHECK: br i1 true
+define void @ifThen_icmp() {
+  br i1 true, label %a, label %b
+
+a:
+  %x = icmp eq i32 undef, undef
+  br label %b
+
+b:
+  ret void
+}
+
+; CHECK-LABEL: @ifThen_fcmp(
+; CHECK: fcmp
+; CHECK: br i1 true
+define void @ifThen_fcmp() {
+  br i1 true, label %a, label %b
+
+a:
+  %x = fcmp oeq float undef, undef
+  br label %b
+
+b:
+  ret void
+}