Revert "lto: enable O3 optimizations on explicit lto modules"

This reverts commit 034a0af.

cc/lto.go

@@ -110,7 +110,6 @@ func (lto *lto) flags(ctx ModuleContext, flags Flags) Flags {
 	}
 	if lto.Properties.LtoEnabled {
 		ltoCFlags := []string{"-flto=thin", "-fsplit-lto-unit"}
-		var ltoCOnlyFlags []string
 		var ltoLdFlags []string
 
 		// The module did not explicitly turn on LTO. Only leverage LTO's
@@ -120,9 +119,6 @@ func (lto *lto) flags(ctx ModuleContext, flags Flags) Flags {
 		// Apply the same for Eng builds as well.
 		if !lto.ThinLTO() || ctx.Config().Eng() {
 			ltoLdFlags = append(ltoLdFlags, "-Wl,--lto-O0")
-		} else {
-			ltoLdFlags = append(ltoLdFlags,"-Wl,--lto-O3")
-			ltoCOnlyFlags = append(ltoCOnlyFlags, "-O3")
 		}
 
 		if Bool(lto.Properties.Whole_program_vtables) {
@@ -168,7 +164,6 @@ func (lto *lto) flags(ctx ModuleContext, flags Flags) Flags {
 		flags.Local.AsFlags = append(flags.Local.AsFlags, ltoCFlags...)
 		flags.Local.LdFlags = append(flags.Local.LdFlags, ltoCFlags...)
 		flags.Local.LdFlags = append(flags.Local.LdFlags, ltoLdFlags...)
-		flags.Local.CFlags = append(flags.Local.CFlags, ltoCOnlyFlags...)
 	}
 	return flags
 }