[flang] Update -falias-analysis help text

As requested by @branach-space on llvm#73111. This makes it clearer that
-f[no-]alias-analysis will always override -O flags, no matter their
ordering.

Author: tblah

clang/include/clang/Driver/Options.td

@@ -6334,8 +6334,8 @@ defm loop_versioning : BoolOptionWithoutMarshalling<"f", "version-loops-for-stri
   PosFlag<SetTrue, [], [ClangOption], "Create unit-strided versions of loops">,
    NegFlag<SetFalse, [], [ClangOption], "Do not create unit-strided loops (default)">>;
 defm alias_analysis : BoolOptionWithoutMarshalling<"f", "alias-analysis",
-  PosFlag<SetTrue, [], [], "Pass alias information on to LLVM (default when optimizing for speed)">,
-  NegFlag<SetFalse, [], [], "Do not pass alias information on to LLVM (default for unoptimized builds)">>;
+  PosFlag<SetTrue, [], [], "Pass alias information on to LLVM (default when optimizing for speed). Overrides -O0.">,
+  NegFlag<SetFalse, [], [], "Do not pass alias information on to LLVM (default for unoptimized builds). Overrides -O flags.">>;
 } // let Visibility = [FC1Option, FlangOption]
 
 def J : JoinedOrSeparate<["-"], "J">,

flang/test/Driver/driver-help-hidden.f90

@@ -26,7 +26,7 @@
 ! CHECK-NEXT: -D <macro>=<value>      Define <macro> to <value> (or 1 if <value> omitted)
 ! CHECK-NEXT: -emit-llvm              Use the LLVM representation for assembler and object files
 ! CHECK-NEXT: -E                      Only run the preprocessor
-! CHECK-NEXT: -falias-analysis        Pass alias information on to LLVM (default when optimizing for speed)
+! CHECK-NEXT: -falias-analysis        Pass alias information on to LLVM (default when optimizing for speed). Overrides -O0.
 ! CHECK-NEXT: -falternative-parameter-statement
 ! CHECK-NEXT:                         Enable the old style PARAMETER statement
 ! CHECK-NEXT: -fapprox-func           Allow certain math function calls to be replaced with an approximately equivalent calculation
@@ -63,7 +63,7 @@
 ! CHECK-NEXT: -flto                   Enable LTO in 'full' mode
 ! CHECK-NEXT: -fms-runtime-lib=<value>
 ! CHECK-NEXT:                         Select Windows run-time library
-! CHECK-NEXT: -fno-alias-analysis     Do not pass alias information on to LLVM (default for unoptimized builds)
+! CHECK-NEXT: -fno-alias-analysis     Do not pass alias information on to LLVM (default for unoptimized builds). Overrides -O flags.
 ! CHECK-NEXT: -fno-automatic          Implies the SAVE attribute for non-automatic local objects in subprograms unless RECURSIVE
 ! CHECK-NEXT: -fno-color-diagnostics  Disable colors in diagnostics
 ! CHECK-NEXT: -fno-integrated-as      Disable the integrated assembler

flang/test/Driver/driver-help.f90

@@ -22,7 +22,7 @@
 ! HELP-NEXT: -D <macro>=<value>      Define <macro> to <value> (or 1 if <value> omitted)
 ! HELP-NEXT: -emit-llvm              Use the LLVM representation for assembler and object files
 ! HELP-NEXT: -E                      Only run the preprocessor
-! HELP-NEXT: -falias-analysis        Pass alias information on to LLVM (default when optimizing for speed)
+! HELP-NEXT: -falias-analysis        Pass alias information on to LLVM (default when optimizing for speed). Overrides -O0.
 ! HELP-NEXT: -falternative-parameter-statement
 ! HELP-NEXT:                         Enable the old style PARAMETER statement
 ! HELP-NEXT: -fapprox-func           Allow certain math function calls to be replaced with an approximately equivalent calculation
@@ -53,7 +53,7 @@
 ! HELP-NEXT: -flto                   Enable LTO in 'full' mode
 ! HELP-NEXT: -fms-runtime-lib=<value>
 ! HELP-NEXT:                         Select Windows run-time library
-! HELP-NEXT: -fno-alias-analysis     Do not pass alias information on to LLVM (default for unoptimized builds)
+! HELP-NEXT: -fno-alias-analysis     Do not pass alias information on to LLVM (default for unoptimized builds). Overrides -O flags.
 ! HELP-NEXT: -fno-automatic          Implies the SAVE attribute for non-automatic local objects in subprograms unless RECURSIVE
 ! HELP-NEXT: -fno-color-diagnostics  Disable colors in diagnostics
 ! HELP-NEXT: -fno-integrated-as      Disable the integrated assembler
@@ -149,7 +149,7 @@
 ! HELP-FC1-NEXT: -emit-llvm              Use the LLVM representation for assembler and object files
 ! HELP-FC1-NEXT: -emit-obj               Emit native object files
 ! HELP-FC1-NEXT: -E                      Only run the preprocessor
-! HELP-FC1-NEXT: -falias-analysis        Pass alias information on to LLVM (default when optimizing for speed)
+! HELP-FC1-NEXT: -falias-analysis        Pass alias information on to LLVM (default when optimizing for speed). Overrides -O0.
 ! HELP-FC1-NEXT: -falternative-parameter-statement
 ! HELP-FC1-NEXT:                         Enable the old style PARAMETER statement
 ! HELP-FC1-NEXT: -fapprox-func           Allow certain math function calls to be replaced with an approximately equivalent calculation
@@ -196,7 +196,7 @@
 ! HELP-FC1-NEXT: -flogical-abbreviations Enable logical abbreviations
 ! HELP-FC1-NEXT: -flto=<value>           Set LTO mode
 ! HELP-FC1-NEXT: -flto                   Enable LTO in 'full' mode
-! HELP-FC1-NEXT: -fno-alias-analysis     Do not pass alias information on to LLVM (default for unoptimized builds)
+! HELP-FC1-NEXT: -fno-alias-analysis     Do not pass alias information on to LLVM (default for unoptimized builds). Overrides -O flags.
 ! HELP-FC1-NEXT: -fno-analyzed-objects-for-unparse
 ! HELP-FC1-NEXT:                         Do not use the analyzed objects when unparsing
 ! HELP-FC1-NEXT: -fno-automatic          Implies the SAVE attribute for non-automatic local objects in subprograms unless RECURSIVE