[clang] [llvm] [clang] Add fixed point precision macros (PR #81207)

[Aaron Ballman via cfe-commits]

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@@ -1097,6 +1150,47 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
              TI.getTypeWidth(TI.getIntMaxType()) &&
          "uintmax_t and intmax_t have different widths?");
 
+  if (LangOpts.FixedPoint) {
+    // Each unsigned type has the same width as their signed type.
+    DefineFixedPointMacros(TI, Builder, "SFRACT", "hr", TI.getShortFractWidth(),
+                           TI.getShortFractScale(), /*Signed=*/true);
+    DefineFixedPointMacros(TI, Builder, "USFRACT", "uhr",
+                           TI.getShortFractWidth(),
+                           TI.getUnsignedShortFractScale(), /*Signed=*/false);
+    DefineFixedPointMacros(TI, Builder, "FRACT", "r", TI.getFractWidth(),
+                           TI.getFractScale(), /*Signed=*/true);
+    DefineFixedPointMacros(TI, Builder, "UFRACT", "ur", TI.getFractWidth(),
+                           TI.getUnsignedFractScale(), /*Signed=*/false);
+    DefineFixedPointMacros(TI, Builder, "LFRACT", "lr", TI.getLongFractWidth(),
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AaronBallman wrote:

Slight preference for using `L` instead of `l` because of font problems where the `l` may look like a `1`. Might be worth making them use the uppercase suffix consistently.

https://github.com/llvm/llvm-project/pull/81207