interp: defer constant ptrtoint to non-byte-sized integers

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: deadprogram

interp/memory.go

@@ -1035,6 +1035,10 @@ func (v *rawValue) set(llvmValue llvm.Value, r *runner) bool {
 			if src.len(r) != size && src.hasPointer() {
 				return false
 			}
+			if llvmValue.Type().TypeKind() == llvm.IntegerTypeKind && uint32(llvmValue.Type().IntTypeWidth()) != size*8 {
+				// Widths like i1 don't fill their bytes, so leave them for runtime.
+				return false
+			}
 			copy(v.buf[:size], src.buf)
 		case llvm.GetElementPtr:
 			ptr := llvmValue.Operand(0)

interp/testdata/ptrtoint.ll

@@ -9,6 +9,7 @@ target triple = "x86_64--linux"
 @main.v5 = global i8 0
 @main.v6 = global { i8, i8 } { i8 ptrtoint (ptr @main.global to i8), i8 7 }
 @main.v7 = global i8 0
+@main.v8 = global i1 0
 
 define void @runtime.initAll() unnamed_addr {
 entry:
@@ -38,6 +39,9 @@ entry:
   ; A global whose initializer can't be computed at compile time.
   %v7 = load i8, ptr getelementptr inbounds (i8, ptr @main.v6, i64 1)
   store i8 %v7, ptr @main.v7
+
+  ; A result narrower than its allocation size is left for runtime.
+  store i1 ptrtoint (ptr inttoptr (i64 2 to ptr) to i1), ptr @main.v8
   ret void
 }
 

interp/testdata/ptrtoint.out.ll

@@ -9,12 +9,14 @@ target triple = "x86_64--linux"
 @main.v5 = local_unnamed_addr global i8 0
 @main.v6 = local_unnamed_addr global { i8, i8 } { i8 ptrtoint (ptr @main.global to i8), i8 7 }
 @main.v7 = local_unnamed_addr global i8 0
+@main.v8 = local_unnamed_addr global i1 false
 
 define void @runtime.initAll() unnamed_addr {
 entry:
   store i8 ptrtoint (ptr @main.global to i8), ptr @main.v3, align 1
   store i8 ptrtoint (ptr @main.global to i8), ptr @main.v5, align 1
   %v7 = load i8, ptr getelementptr inbounds (i8, ptr @main.v6, i64 1), align 1
   store i8 %v7, ptr @main.v7, align 1
+  store i1 ptrtoint (ptr inttoptr (i64 2 to ptr) to i1), ptr @main.v8, align 1
   ret void
 }