Revert "ADT: add <bit> header, implement C++20 bit_cast, use"

Bots sad. Looks like missing std::is_trivially_copyable.

llvm-svn: 341730

1 files changed, 13 insertions, 8 deletions

diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMAddressingModes.h b/llvm/lib/Target/ARM/MCTargetDesc/ARMAddressingModes.h
index e450d3f5d75..f472b215431 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMAddressingModes.h
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMAddressingModes.h
@@ -627,22 +627,27 @@ namespace ARM_AM {
   //
   inline float getFPImmFloat(unsigned Imm) {
     // We expect an 8-bit binary encoding of a floating-point number here.
+    union {
+      uint32_t I;
+      float F;
+    } FPUnion;
 
     uint8_t Sign = (Imm >> 7) & 0x1;
     uint8_t Exp = (Imm >> 4) & 0x7;
     uint8_t Mantissa = Imm & 0xf;
 
-    //   8-bit FP    IEEE Float Encoding
+    //   8-bit FP    iEEEE Float Encoding
     //   abcd efgh   aBbbbbbc defgh000 00000000 00000000
     //
     // where B = NOT(b);
-    uint32_t I = 0;
-    I |= Sign << 31;
-    I |= ((Exp & 0x4) != 0 ? 0 : 1) << 30;
-    I |= ((Exp & 0x4) != 0 ? 0x1f : 0) << 25;
-    I |= (Exp & 0x3) << 23;
-    I |= Mantissa << 19;
-    return bit_cast<float>(F);
+
+    FPUnion.I = 0;
+    FPUnion.I |= Sign << 31;
+    FPUnion.I |= ((Exp & 0x4) != 0 ? 0 : 1) << 30;
+    FPUnion.I |= ((Exp & 0x4) != 0 ? 0x1f : 0) << 25;
+    FPUnion.I |= (Exp & 0x3) << 23;
+    FPUnion.I |= Mantissa << 19;
+    return FPUnion.F;
   }
 
   /// getFP16Imm - Return an 8-bit floating-point version of the 16-bit